Clinical outcomes of neoadjuvant therapy followed by selective inguinal lymph node dissection and total mesorectal excision for metastasised rectal or anal canal adenocarcinoma

Clinical outcomes of neoadjuvant therapy followed by selective inguinal lymph node dissection and total mesorectal excision for metastasised rectal or anal canal adenocarcinoma | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Clinical outcomes of neoadjuvant therapy followed by selective inguinal lymph node dissection and total mesorectal excision for metastasised rectal or anal canal adenocarcinoma Hiroshi Hasegawa, Takeru Matsuda, Kimihiro Yamashita, Ryuichiro Sawada, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1997231/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Dec, 2022 Read the published version in Langenbeck's Archives of Surgery → Version 1 posted 7 You are reading this latest preprint version Abstract Purpose Rectal or anal canal adenocarcinoma with inguinal lymph node metastasis (ILNM) is rare and is associated with poor prognostic outcomes. This study aimed to elucidate the clinical significance of neoadjuvant therapy followed by selective inguinal lymph node dissection and total mesorectal excision for rectal or anal canal adenocarcinoma with clinically suspected ILNM. Methods This study enrolled 15 consecutive patients who underwent neoadjuvant therapy and curative resection for rectal or anal canal adenocarcinoma with clinically suspected ILNM between 2005 and 2019 at a single institution. Inguinal lymph node dissection was selectively performed on the side of suspected metastasis before neoadjuvant therapy. Short- and long-term outcomes were retrospectively reviewed. Results Out of the15 patients, 11 were treated with neoadjuvant chemoradiation, three with chemotherapy, and one with chemoradiation followed by chemotherapy. Six patients had negative fluorodeoxyglucose (FDG) accumulation in inguinal lymph nodes on preoperative FDG-positron emission tomography (FDG-PET) scan, and their inguinal lymph nodes were also pathologically negative for metastasis. Of the nine patients who had positive FDG accumulation, four had pathologically positive inguinal lymph nodes. Seven patients (46.7%) had inguinal seroma postoperatively. Five-year-overall survival was 77.5%, and 5-year-relapse-free survival was 64.2%. No patient had a recurrence in the inguinal region. Conclusion In patients with rectal or anal canal adenocarcinoma associated with clinical ILNM, radical resection with neoadjuvant therapy provides a good long-term survival. Rectal cancer anal cancer adenocarcinoma inguinal lymph node dissection neoadjuavnt therapy metastasis Figures Figure 1 Figure 2 Introduction The frequency of metastasis to the inguinal lymph nodes in advanced rectal or anal canal adenocarcinoma is 0.3–6%, depending on the tumor depth and dentate line involvement [ 1 – 4 ]. However, the treatment strategy for rectal or anal canal adenocarcinoma with inguinal lymph node metastasis (ILNM) has not yet been established. According to reports prior to 2000, rectal or anal adenocarcinoma with ILNM had an extremely poor prognosis, and palliative chemotherapy was recommended [ 5 – 7 ]. With the advancements in preoperative imaging [ 8 , 9 ], perioperative treatments [ 10 – 14 ], chemotherapy after recurrence [ 15 , 16 ], and the development of surgical techniques [ 17 – 19 ], the treatment outcomes of rectal adenocarcinoma have improved over the past two decades. Recent reports have shown an improved 5-year survival rate of 40–60% for primary rectal cancer patients with solitary ILNM [ 4 , 20 – 22 ]. Preoperative treatment is important in terms of local control in the treatment of advanced rectal adenocarcinoma without ILNM; unfortunately, there are only limited reports on preoperative treatment in rectal or anal adenocarcinoma with ILNM. Furthermore, there is a lack of reports on surgical techniques for inguinal lymph node dissection, including the extent of dissection and how to perform it. In this study, we demonstrated our standard surgical technique for inguinal lymph node dissection with en bloc resection of the superficial inguinal lymph nodes. Owing to the high frequency of lymphatic leakage after inguinal lymph node dissection, prophylactic bilateral dissection was not performed; instead it was performed only on the side where metastasis was suspected on preoperative imaging. We hope that our short- and long-term results will provide a better understanding of treatment strategies for rectal or anal adenocarcinoma with clinically suspected ILNM. Methods Patients This was a single-center, retrospective study of 15 patients with rectal or anal adenocarcinoma associated with suspected ILNM on preoperative imaging. Since 2005, our institution has been performing chest and abdominal computed tomography (CT) scans for patients with advanced lower rectal or anal adenocarcinoma, and if there are no contraindications, abdominal contrast-enhanced CT and positron emission tomography (PET)-CT/ magnetic resonance imaging (MRI) examinations have been performed. Prior to treatment, two or more radiologists were consulted for ILNM diagnosis, and a conference consisting of gastrointestinal surgeons, gastroenterologists, and radiologists made the final determination of clinical metastasis. ILNM has no strict definition; however, a short lymph node diameter of 1 cm or more, an abnormal shape, and an abnormal accumulation of fluorodeoxyglucose(FDG) were defined as clinically positive for metastasis. The definition of the anal canal and rectal adenocarcinoma was based on the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma. Briefly, those tumors with their center above the superior border of the puborectal sling were considered as rectal adenocarcinoma, and those below were considered as anal canal adenocarcinoma. Patients with concurrent advanced cancer in other sites were excluded from this study. Patients who underwent curative resection for rectal or anal canal adenocarcinoma with clinical ILNM at Kobe University Hospital between 2005 and 2019 were included in this study. This retrospective study was approved by the Institutional Ethics Review Board of the Kobe University Hospital (IRB reference number: B210222). Neoadjuvant treatment Chemoradiotherapy was administered unless radiation was contraindicated or the patient requested chemotherapy. Patients received chemoradiotherapy before surgery with a combination of oral 5FU (capecitabine or tegafur-uracil (UFT)/leucovorin (LV)) and 45–50.4 Gy of radiation. Patients with contraindications to radiation therapy and those who requested chemotherapy were administered chemotherapy, and the regimen was based on the patient's age, general condition, and preference. One patient who was referred to our hospital after chemoradiation therapy at another institution received additional chemotherapy followed by radical surgery. Radical surgery was performed 5–8 weeks after chemoradiation therapy or 2–8 weeks after chemotherapy. Surgical procedure If the distance between the lower margin of the tumor and dentate line > 2 cm and a distal margin could be maintained, then a low anterior resection was performed. If the distance between the lower margin of the tumor and dentate line was < 2 cm, then an abdominoperineal resection was performed. Total pelvic exenteration was performed if there was vaginal, bladder, or prostate involvement. If metastasis was suspected in the lateral pelvic lymph nodes on preoperative imaging, subsequent lateral lymph node dissection was performed. Inguinal lymph node dissection was performed before total mesorectal excision (TME) and lateral lymph node dissection. Inguinal Lymph Node Dissection Due consideration was given to ensure resection of the suspected metastatic lymph nodes by resecting them together with the surrounding fatty tissue. Therefore, the extent of resection varied slightly depending on the degree of inguinal metastasis. The basic surgical technique is as follows: First, a 10–12 cm skin incision was made in the cephalocaudal direction, subcutaneous fat was incised with an electrocautery scalpel, and a skin flap was made in the medial and lateral directions after the incision of the superficial fascia. While ligating and dissecting the blood vessels and lymphatics, the external oblique aponeurosis was exposed to a cephalad, which was the cephalic end of the dissection (Online Resource 1). The fat was subsequently removed including the inguinal lymph nodes to expose the fascia lata laterally and the accessory saphenous vein caudally, followed by exposure of the fascia lata and fossa ovalis. The blood vessels and lymphatic vessels that pass between the fossa ovalis and the inguinal fat were ligated and dissected to prevent postoperative lymph leakage (Online Resource 2). Finally, the great saphenous vein was exposed, and the fat inside this vein was removed from the caudad to the cephalad to expose the fascia lata (Online Resource 3). We have presented a photograph and anatomical diagram of the post inguinal dissection (Fig. 1 ). Follow-up after surgery Follow-up was done every 3 months for the first 5 years and every 6 months thereafter. Serum CEA and CA19-9 were measured every 3 months as tumor markers. A thoracoabdominal CT scan was performed every 6 months. If anastomosis was performed, colonoscopy was performed at 1, 2, 3, and 5 years postoperatively. If metastasis was suspected by tumor markers or thoracoabdominal CT scan, then PET or MRI was performed. Local recurrence was defined as recurrence in the pelvis. Statistical analysis Statistical analysis was performed using JMP version 10 (SAS Institute Inc., Cary, NC, USA). Continuous variables were represented with median and range. Survival analysis was performed using the Kaplan-Meier method. Results Patient characteristics Out of the 15 cases, four had anal canal adenocarcinoma and the remaining patients had rectal adenocarcinoma. Demographic and clinical characteristics are shown in Table 1 . The median age of patients was 66 years (range: 71–78). Ten patients (66.7%) had dentate line involvement, and the distance between the tumor and dentate line was within 5 cm in the other five patients. Eleven patients (73.3%) were treated with preoperative chemoradiotherapy as neoadjuvant therapy. Three patients were treated with preoperative chemotherapy, including one patient who received seven courses of FOLFOX plus bevacizumab at his request, one patient who received six courses of FOLFOXIRI plus bevacizumab at his request, and one patient who received six courses of FOLFOX because she had previously been treated with radiation therapy for uterine cancer and could not receive chemoradiation. One patient was referred after preoperative chemoradiotherapy at another hospital and was operated on after seven courses of FOLFOX plus cetuximab. Table 1 Demographic and clinical characteristics Characteristics Case (%) Gender Male 8 (53.3) Female 7 (46.7) Age, y Median (range) 66 (41–78) ASA class ASA 1–2 14 (93.3) ASA > 2 1 (6.7) Distance from the anal verge, cm Median (range) 0 (0–5) Clinical tumor stage a T2 1 (6.7) T3 4 (26.7) T4 10 (66.7) Clinical nodal stage a N1 2 (13.3) N2 13 (86.7) Neoadjuvant therapy CRT 11 (73.3) CT 3 (20.0) CRT followed by CT 1 (6.7) a Tumor were classified according to the eighth edition of the Union for International Cancer Control tumor-node-metastasis cancer staging system. Data are presented as n (%) ASA , American Society of Anesthesiologists; CRT , chemoradiotherapy; CT , chemotherapy. Operative outcomes and pathological findings Operative outcomes and pathological findings are listed in Table 2 . Unilateral inguinal dissection was performed in six patients and bilateral inguinal dissection in nine patients. Seven patients (43.8%) had inguinal seroma of Clavien-dindo classification Grade 2 or higher. Reoperation for inguinal seroma was necessary in three cases (20.0%); lymphatic ligation was performed in two cases, and drainage was performed in one case because of infection. Preoperative treatment resulted in a marked effect in three patients (20.0%). Two patients had positive circumferential resection margins. Table 2 Operative and pathological outcomes Characteristics Case (%) Approach Open 6 (40.0) Laparoscopic 9 (60.0) Surgical procedure Low anterior resection 3 (20.0) Abdominoperineal resection 10 (66.7) Total pelvic exenteration 2 (13.3) Postoperative complications, Clavient-dindo classification grade≧Ⅱ Inguinal seroma 7 (46.7) Superficial wound infection 5 (33.3) Intra-pelvic abscess 1 (6.7) Small bowel obstruction 1 (6.7) Histology Well/moderately differentiated 13 (86.7) Poorly differentiated/mucinous 2 (13.3) Pathological tumor stage a T0 3 (20.0) T1 0 (0) T2 3 (20.0) T3 4 (26.7) T4 5 (33.3) Pathological nodal stage a N0 8 (53.3) N1 4 (26.7) N2 3 (20.0) Proximal resection margin positive 0 (0) Distal resection margin positive 0 (0) Circumferential resection margin positive 2 (13.3) a Tumor were classified according to the eighth edition of the Union for International Cancer Control tumor-node-metastasis cancer staging system Fluorodeoxyglucose accumulation in the inguinal region FDG-PET scans were performed after neoadjuvant therapy in 14 patients (93.3%). One patient who did not undergo an FDG-PET scan after preoperative treatment underwent an FDG-PET scan before neoadjuvant therapy, and no FDG accumulation was observed in that case. Six patients had negative FDG accumulation in the inguinal lymph nodes on preoperative FDG-PET scan, and their inguinal lymph nodes were also pathologically negative for metastasis. Of the nine patients who had positive FDG accumulation, four (44.4%) had pathologically positive ILNM (Table 3 ). Table 3 Neoadjuvant treatment, preoperative fluorodeoxyglucose PET-CT/MRI findings, pathological findings, and long-term outcomes Age Sex Neoadjuvant treatment Before neoadjuvant therapy After neoadjuvant therapy ILN dissection Pathological findings Site of recurrence/ interval from treatment to recurrence Outcome/ follow-up Maximum size of ILN (mm) SUVmax/ clinical diagnosis Maximum size of ILN (mm) SUVmax/ clinical diagnosis Number of metastatic ILN Number of ILN harvested pT stage a pN stage a Response to chemotherapy or radiation b 78 F CRT 21 - 16 2.12/ P B 4 13 2 2 Grade 1a Local/6y0m Alive/8y10m 66 M CRT followed by CT 14 - 14 3.13/ P U 1 4 4a 1 Grade 1b Local /1y0m Alive/3y4m 62 M CRT 11 2.31/ P 11 3.58/ P B 1 2 3 1 Grade 1b No /7y1m Alive/7y1m 71 F CRT 20 2.49/ P 19 2.49/ P U 1 2 3 1 Grade 2 Lung /1y1m Died/3y10m 41 F CRT 12 - 9 1.86/ N B 0 6 2 0 Grade 1a No/16y7m Alive/16y7m 66 F CRT 23 5.22/ P 10 1.71/ N B 0 5 0 0 Grade 3 No/9y11m Alive/9y11m 71 M CRT 11 1.72/ N 9 - B 0 9 0 0 Grade 3 No/8y7m Alive/8y7m 64 F CRT 15 2.72/ P 7 1.87/ N U 0 2 2 0 Grade 2 No/5y6m Alive/5y6m 78 F CT 11 10.46/ P 8 1.52/ N B 0 14 4b 0 Grade 1a No/3y0m Alive/3y0m 57 M CT 21 14.60/ P 9 1.84/ N U 0 2 0 0 Grade 3 No/2y4m Alive/2y4m 71 M CRT 12 3.60/ P 8 2.12/ P U 0 2 4a 0 Grade 1b No/8y6m Alive/8y6m 54 F CRT 7 1.95/ N 7 3.12/ P U 0 7 3 1 Grade 2 No/4y1m Alive/4y1m 67 M CRT 12 1.97/ N 12 3.95/ P B 0 18 3 2 Grade 1b Local/4y6m Alive/5y3m 62 M CRT 13 7.04/ P 9 3.68/ P B 0 11 4b 0 Grade 1b Local/7m Died/2y7m 62 M CT 10 - 10 3.14/ P B 0 11 4b 2 Grade 1a Lung /1y0m Died/1y6m a Tumor were classified according to the eighth edition of the Union for International Cancer Control tumor-node-metastasis cancer staging system. b Histological criteria of primary rectal cancer for the assessment of response to chemotherapy or radiation were classified according to the 3rd English edition of the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma [ 26 ]: Grade 0 (No effect), Grade 1a (Minimal effect: Tumor cell change < 1/3), Grade 1b (Mild effect: Tumor cell change 2/3), Grade 3 (Marked effect: No viable tumor cells are observed) M , male; F , female; ILN , inguinal lymph node; SUVmax , the maximum standardized uptake value; P , positive; N , negative; B , bilateral; U , unilateral; CRT , chemoradiotherapy; CT , chemotherapy; PET-CT/MRI , positron emission tomography/ magnetic resonance image Adjuvant therapy Nine patients (66.7%) received postoperative adjuvant chemotherapy. Three patients received 5FU/LV, two received FOLFOX therapy and four received CapeOX therapy. Long-term outcomes The median follow-up period was 63 months. The 3- and 5-year overall survival rates were 86.2% and 77.5%, respectively. The 3- and 5-year recurrence-free survival rates were 73.3% and 64.2%, respectively (Fig. 2 ). Discussion Rectal or anal canal adenocarcinoma with ILNM is rare, and is often encountered clinically and the treatment strategy is challenging. Systemic chemotherapy is recommended for patients with unresectable distant metastasis; however, no clear treatment strategy has been established for patients with resectable distant metastasis or no metastasis other than ILNM. There are no prospective clinical studies in patients with rectal or anal canal adenocarcinoma with only ILMN; only retrospective studies in a small number of cases have been reported. While long-term survival of more than 5 years was extremely rare in reports prior to 2000 [ 5 – 7 ], recent reports have reported 5-year survival rates of 15.9–55.2% [ 4 , 20 – 24 ]. This study had the highest number of cases of radical resection for simultaneous metastases and the most favorable outcomes among papers reporting 5-year overall survival rates of 50% or greater [ 20 – 22 ]. Lymph node metastasis of rectal or anal canal adenocarcinoma often occurs in the mesorectum, and total mesorectal excision is the foremost procedure in the treatment of rectal or anal canal adenocarcinoma. However, lymph node metastasis of rectal or anal canal adenocarcinoma can also extend beyond the mesorectum, with typical examples being para-aortic lymph node metastasis, lateral lymph node metastasis, and inguinal lymph node metastasis. The 5-year recurrence-free survival rate for lymph node dissection for para-aortic lymph node metastases is about 15%, with limited efficacy [ 25 , 26 ]. Lateral lymph node dissection for lateral lymph node metastases is considered effective and has been reported to reduce local recurrence in a randomized controlled trial (RCT) [ 17 ]. Inguinal lymph node dissection for inguinal lymph node metastases has exhibited good results in some studies [ 20 – 22 ], including in this study, and may potentially be effective. The common technique for dissecting the inguinal lymph nodes for rectal or anal canal adenocarcinoma is to dissect the shallow inguinal lymph nodes, but the extent of dissection has not been established. We considered it important to resect lymph nodes suspected of metastasis along with surrounding fat after neoadjuvant therapy. The fascia lata, fossa ovalis, accessory saphenous vein, and great saphenous vein are good anatomical landmarks for inguinal lymph node dissection. Few reports mentioned inguinal seroma after inguinal dissection for rectal cancer, and one study reported it in four of 17 patients (23.5%) who underwent inguinal lymph node dissection [ 20 ]. In another study of 240 patients who underwent inguinal dissection for malignant melanoma, 51.2% had wound complications and 21.5% had seroma [ 27 ]. In this study, seven of 15 patients (43.8%) who underwent inguinal lymph node dissection had inguinal seroma, and three (20%) required reoperation, which was relatively a high complication rate. Although the frequency of inguinal seroma varies depending on the extent of lymph node dissection and the definition of the complication, postoperative inguinal seroma is an important complication after inguinal lymph node dissection and may be the cause of hesitation to dissect. The indications for preoperative treatment of rectal cancer with ILMN may require further investigation. Results of several RCTs have indicated that chemoradiotherapy improved local control [ 11 , 28 ] and total neoadjuvant therapy improved disease-free survival [ 10 , 12 ]; however, there is no clear evidence of overall survival improvement. There is a report signifying a 55.2% 5-year survival rate after radical surgery without neoadjuvant treatment for rectal cancer with ILMN. In this study, all patients were treated preoperatively, and no pathologic inguinal lymph node metastasis was observed in patients with negative FDG uptake in the inguinal region after neoadjuvant therapy. Therefore, inguinal lymph node dissection may be omitted in cases in which FDG uptake is negative after neoadjuvant therapy. There are several limitations in this study. First, this was a retrospective study that may include bias. Second, the inguinal lymph node metastasis may be over-estimated because it was determined clinically rather than pathologically. However, we felt that a clinical diagnosis was appropriate, as a preoperative needle biopsy was not easy to perform because of the proximity of important blood vessels in the inguinal region, and an exploratory biopsy could obscure the anatomy at the time of inguinal lymph node dissection. Third, this study did not include patients with resectable distant metastases in the liver or lungs other than the inguinal lymph nodes; hence, it was not possible to demonstrate what treatment would be best in these patients. Fourth, this was a single-center study with a small number of cases. To conclude, radical surgery including inguinal lymph node dissection after adjuvant therapy has demonstrated a better long-term prognosis in patients with rectal or anal canal adenocarcinoma associated with ILNM, although a high rate of inguinal seroma was observed. Declarations Funding: This work was supported by Japan Society for the Promortion of Science KAKENHI (grant number 21K16446). Competing Interests: The authors have no competing interests to declare that are relevant to the content of this article. Ethical approval: This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Institutional Ethics Review Board of the Kobe University Hospital (reference number: B210222; |Date of approval|). Informed Consent: Ethical approval was waived by the Institutional Ethics Review Board of the Kobe University Hospital in view of the retrospective nature of the study and all the procedures being performed were part of the routine care. Data Availability statement: The data that support the findings of this study can be made available from the corresponding author upon reasonable request. Authors’ Contribution: All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Hiroshi Hasegawa, Takeru Matsuda, Kimihiro Yamashita and Ryuichiro Sawada. The first draft of the manuscript was written by Hiroshi Hasegawa and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Acknowledgments: This work was supported by Japan Society for the Promortion of Science KAKENHI (grant number 21K16446). References Hamano T, Homma Y, Otsuki Y, Shimizu S, Kobayashi H, Kobayashi Y (2010) Inguinal lymph node metastases are recognized with high frequency in rectal adenocarcinoma invading the dentate line. The histological features at the invasive front may predict inguinal lymph node metastasis. Colorectal Dis 12:e200–e205. https://doi.org/10.1111/j.1463-1318.2009.02134.x Shiratori H, Nozawa H, Kawai K, et al (2020) Risk factors and therapeutic significance of inguinal lymph node metastasis in advanced lower rectal cancer. Int J Colorectal Dis 35:655–664. https://doi.org/10.1007/s00384-020-03520-2 Wang R, Wu P, Shi D, et al (2014) Risk factors of synchronous inguinal lymph nodes metastasis for lower rectal cancer involving the anal canal. PLoS One 9:e111770. https://doi.org/10.1371/journal.pone.0111770 Saiki Y, Yamada K, Tanaka M, Fukunaga M, Irei Y, Suzuki T (2022) Prognosis of anal canal adenocarcinoma versus lower rectal adenocarcinoma in Japan: a propensity score matching study. Surg Today 52:420–430. https://doi.org/10.1007/s00595-021-02350-1 Luna-Pérez P, Corral P, Labastida S, Rodríguez-Coria D, Delgado S (1999) Inguinal lymph node metastases from rectal adenocarcinoma. J Surg Oncol 70:177–180. https://doi.org/10.1002/(sici)1096-9098(199903)70:33.0.co;2-0 Tocchi A, Lepre L, Costa G, et al (1999) Rectal cancer and inguinal metastases: prognostic role and therapeutic indications. Dis Colon Rectum 42:1464–1466. https://doi.org/10.1007/BF02235048 Mesko TW, Rodriguez-Bigas MA, Petrelli NJ (1994) Inguinal lymph node metastases from adenocarcinoma of the rectum. Am J Surg 168:285–287. https://doi.org/10.1016/s0002-9610(05)80204-1 Caruso R, Vicente E, Quijano Y, et al (2021) Role of 18F-PET-CT to predict pathological response after neoadjuvant treatment of rectal cancer. Discov Oncol 12:16. https://doi.org/10.1007/s12672-021-00405-w Uemura M, Ikeda M, Handa R, et al (2021) The efficiency of 18F-FDG-PET/CT in the assessment of tumor response to preoperative chemoradiation therapy for locally recurrent rectal cancer. BMC Cancer 21:1132. https://doi.org/10.1186/s12885-021-08873-7 Conroy T, Bosset JF, Etienne PL, et al (2021) Neoadjuvant chemotherapy with FOLFIRINOX and preoperative chemoradiotherapy for patients with locally advanced rectal cancer (UNICANCER-PRODIGE 23): a multicentre, randomised, open-label, phase 3 trial. Lancet Oncol 22:702–715. https://doi.org/10.1016/S1470-2045(21)00079-6 Bosset JF, Collette L, Calais G, et al (2006) Chemotherapy with preoperative radiotherapy in rectal cancer. N Engl J Med 355:1114–1123. https://doi.org/10.1056/NEJMoa060829 Bahadoer RR, Dijkstra EA, van Etten B, et al (2021) Short-course radiotherapy followed by chemotherapy before total mesorectal excision (TME) versus preoperative chemoradiotherapy, TME, and optional adjuvant chemotherapy in locally advanced rectal cancer (RAPIDO): a randomised, open-label, phase 3 trial. Lancet Oncol 22:29–42. https://doi.org/10.1016/S1470-2045(20)30555-6 Chakravarthy AB, Zhao F, Meropol NJ, et al (2020) Intergroup randomized Phase III study of postoperative oxaliplatin, 5-fluorouracil, and leucovorin versus oxaliplatin, 5-fluorouracil, leucovorin, and bevacizumab for patients with Stage II or III rectal cancer receiving preoperative chemoradiation: a trial of the ECOG-ACRIN research group (E5204). Oncologist 25:e798–e807. https://doi.org/10.1634/theoncologist.2019-0437 Hong YS, Nam BH, Kim KP, et al (2014) Oxaliplatin, fluorouracil, and leucovorin versus fluorouracil and leucovorin as adjuvant chemotherapy for locally advanced rectal cancer after preoperative chemoradiotherapy (ADORE): an open-label, multicentre, phase 2, randomised controlled trial. Lancet Oncol 15:1245–1253. https://doi.org/10.1016/S1470-2045(14)70377-8 Tabernero J, Grothey A, Van Cutsem E, et al (2021) Encorafenib plus cetuximab as a new standard of care for previously treated BRAF V600E-mutant metastatic colorectal cancer: updated survival results and subgroup analyses from the Beacon study. J Clin Oncol 39:273–284. https://doi.org/10.1200/JCO.20.02088 Loupakis F, Cremolini C, Masi G, et al (2014) Initial therapy with FOLFOXIRI and bevacizumab for metastatic colorectal cancer. N Engl J Med 371:1609–1618. https://doi.org/10.1056/NEJMoa1403108 Fujita S, Mizusawa J, Kanemitsu Y, et al (2017) Mesorectal excision with or without lateral lymph node dissection for clinical Stage II/III lower rectal cancer (JCOG0212): A multicenter, randomized controlled, noninferiority trial. Ann Surg 266:201–207. https://doi.org/10.1097/SLA.0000000000002212 Heald RJ, Husband EM, Ryall RD (1982) The mesorectum in rectal cancer surgery–the clue to pelvic recurrence? Br J Surg 69:613–616. https://doi.org/10.1002/bjs.1800691019 MacFarlane JK, Ryall RD, Heald RJ (1993) Mesorectal excision for rectal cancer. Lancet 341:457–460. https://doi.org/10.1016/0140-6736(93)90207-w Hagemans JAW, Rothbarth J, van Bogerijen GHW, et al (2019) Treatment of inguinal lymph node metastases in patients with rectal adenocarcinoma. Ann Surg Oncol 26:1134–1141. https://doi.org/10.1245/s10434-019-07191-4 Tanabe T, Shida D, Komukai S, Nakamura Y, Tsukamoto S, Kanemitsu Y (2019) Long-term outcomes after surgical dissection of inguinal lymph node metastasis from rectal or anal canal adenocarcinoma. BMC Cancer 19:733. https://doi.org/10.1186/s12885-019-5956-y Abd El Aziz MA, McKenna NP, Jakub JW, et al (2022) Rectal cancer with synchronous inguinal lymph node metastasis without distant metastasis. A call for further oncological evaluation. Eur J Surg Oncol 48:1100–1103. https://doi.org/10.1016/j.ejso.2021.12.018 Adachi T, Hinoi T, Egi H, Ohdan H (2013) Surgical treatment for isolated inguinal lymph node metastasis in lower rectal adenocarcinoma patients improves outcome. Int J Colorectal Dis 28:1675–1680. https://doi.org/10.1007/s00384-013-1746-1 Su Z, Guo ZW, Mao YP, et al (2017) Anal adenocarcinoma requires prophylactic inguinal nodal treatment: results from a single Chinese institution. J Cancer 8:1097–1102. https://doi.org/10.7150/jca.17513 Sakamoto J, Ozawa H, Nakanishi H, Fujita S (2020) Oncologic outcomes after resection of para-aortic lymph node metastasis in left-sided colon and rectal cancer. PLoS One 15:e0241815. https://doi.org/10.1371/journal.pone.0241815 Nakai N, Yamaguchi T, Kinugasa Y, et al (2017) Long-term outcomes after resection of para-aortic lymph node metastasis from left-sided colon and rectal cancer. Int J Colorectal Dis 32:999–1007. https://doi.org/10.1007/s00384-017-2806-8 Faut M, Heidema RM, Hoekstra HJ, et al (2017) Morbidity after inguinal lymph node dissections: it is time for a change. Ann Surg Oncol 24:330–339. https://doi.org/10.1245/s10434-016-5461-3 van Gijn W, Marijnen CA, Nagtegaal ID, et al (2011) Preoperative radiotherapy combined with total mesorectal excision for resectable rectal cancer: 12-year follow-up of the multicentre, randomised controlled TME trial. Lancet Oncol 12:575–582. https://doi.org/10.1016/S1470-2045(11)70097-3 Additional Declarations No competing interests reported. Supplementary Files OnlineResource1.mp4 Online Resource 1: Video from skin incision to exposure of the cephalic end of the dissection OnlineResource2.mp4 Online Resource 2: Video of inguinal lymph node dissection around the fossa ovalis and outside the accessory saphenous vein OnlineResource3.mp4 Online Resource 3: Video of inguinal lymph node dissection inside the great saphenous vein Cite Share Download PDF Status: Published Journal Publication published 28 Dec, 2022 Read the published version in Langenbeck's Archives of Surgery → Version 1 posted Editorial decision: Major revision 13 Oct, 2022 Reviews received at journal 22 Sep, 2022 Reviewers agreed at journal 10 Sep, 2022 Reviewers invited by journal 10 Sep, 2022 Editor assigned by journal 26 Aug, 2022 Submission checks completed at journal 25 Aug, 2022 First submitted to journal 25 Aug, 2022 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1997231","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":131624151,"identity":"c00ac615-95bc-4b15-bfaf-2e0be3d6c816","order_by":0,"name":"Hiroshi Hasegawa","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/ElEQVRIiWNgGAWjYBACAwhlA8QJzAyMDTBxHoJa0kjXchhdCx5gzn784cMvNeej+dkTmA0+7rBhMDjA/PADg8wdnFose3KMjWWO3c6d2fOAOXHmmTSgFjZjCQaeZ7gddiCHTVqC7XbuhhsJzId52w7XbzjAYAb0y2HcWs4/f/5b4t+53P0QLf+BhrB/w6/lRoIZ48e2A7kbJBKYk3nbDgC18BCw5cYbY2nGvuTcGWceNhvOPJPMIHmYp1giAZ9fzqc//Pjjm11uf3vyYYmPO+wY+I63b/zwsQd3iIEAMyTeYJHCDMSJPQfwamH8gSn2A7+WUTAKRsEoGFEAALkzWitubXTSAAAAAElFTkSuQmCC","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Hiroshi","middleName":"","lastName":"Hasegawa","suffix":""},{"id":131624152,"identity":"c68aaed1-0d2d-4833-8305-1ee33a9683cd","order_by":1,"name":"Takeru Matsuda","email":"","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Takeru","middleName":"","lastName":"Matsuda","suffix":""},{"id":131624153,"identity":"036635d3-f927-4edd-9427-be9a2fc055af","order_by":2,"name":"Kimihiro Yamashita","email":"","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Kimihiro","middleName":"","lastName":"Yamashita","suffix":""},{"id":131624154,"identity":"d1143ed8-005b-4e43-ad8c-a5012c7e9dea","order_by":3,"name":"Ryuichiro Sawada","email":"","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ryuichiro","middleName":"","lastName":"Sawada","suffix":""},{"id":131624155,"identity":"b86d8490-f768-4c7c-bd9f-20cc33c9f83e","order_by":4,"name":"Hitoshi Harada","email":"","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hitoshi","middleName":"","lastName":"Harada","suffix":""},{"id":131624156,"identity":"cf1843cc-be7f-4dd6-92ed-79d3a0d7fce1","order_by":5,"name":"Naoki Urakawa","email":"","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Naoki","middleName":"","lastName":"Urakawa","suffix":""},{"id":131624157,"identity":"4f5aef91-3681-44f8-bee5-37be6a0b2f17","order_by":6,"name":"Hironobu Goto","email":"","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hironobu","middleName":"","lastName":"Goto","suffix":""},{"id":131624158,"identity":"eb2d97a4-2237-4da0-a4d5-dcb384cac7bb","order_by":7,"name":"Shingo Kanaji","email":"","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Shingo","middleName":"","lastName":"Kanaji","suffix":""},{"id":131624159,"identity":"68b7d2ca-29b2-44ea-9a0e-6e807b163a01","order_by":8,"name":"Taro Oshikiri","email":"","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Taro","middleName":"","lastName":"Oshikiri","suffix":""},{"id":131624160,"identity":"f254e209-4e7e-497d-bc46-bbc93f4149f7","order_by":9,"name":"Yoshihiro Kakeji","email":"","orcid":"","institution":"Kobe University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yoshihiro","middleName":"","lastName":"Kakeji","suffix":""}],"badges":[],"createdAt":"2022-08-25 09:44:25","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1997231/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1997231/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00423-022-02739-7","type":"published","date":"2022-12-28T18:07:35+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":25797190,"identity":"a6addbd8-5406-4a7c-992c-b3dbe634480e","added_by":"auto","created_at":"2022-08-29 14:29:41","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":616609,"visible":true,"origin":"","legend":"\u003cp\u003ePhotographs and anatomical drawings after inguinal lymph node dissection. The lymph nodes above the fossa ovalis are resected with sufficient margin (A and C①). The lymph nodes inside the great saphenous vein are dissected (B and C②).\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-1997231/v1/6ea30eb0a6ef991bbd12677a.jpg"},{"id":25797191,"identity":"1ff31fb8-8da1-4189-98ea-06f51abab149","added_by":"auto","created_at":"2022-08-29 14:29:41","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":243793,"visible":true,"origin":"","legend":"\u003cp\u003eOverall survival curve (\u003cstrong\u003ea\u003c/strong\u003e) and relapse-free survival curve (\u003cstrong\u003eb\u003c/strong\u003e) for 15 rectal or anal canal adenocarcinoma patients.\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-1997231/v1/fdf0ca09f8385213f1be3327.jpg"},{"id":44715087,"identity":"fcf3f293-90ce-4425-90ca-3db63da162c5","added_by":"auto","created_at":"2023-10-16 18:13:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":510069,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1997231/v1/1975eefd-3b24-47f5-8063-01bd8cd60a68.pdf"},{"id":25797192,"identity":"554764a8-438c-4546-a521-4965496cf077","added_by":"auto","created_at":"2022-08-29 14:29:43","extension":"mp4","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":71734233,"visible":true,"origin":"","legend":"\u003cp\u003eOnline Resource 1: Video from skin incision to exposure of the cephalic end of the dissection\u003c/p\u003e","description":"","filename":"OnlineResource1.mp4","url":"https://assets-eu.researchsquare.com/files/rs-1997231/v1/30e95bf7bc9e1673d7fd761e.mp4"},{"id":25797193,"identity":"50b60f65-9461-4484-9350-4b31153cb0e2","added_by":"auto","created_at":"2022-08-29 14:29:43","extension":"mp4","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":68092827,"visible":true,"origin":"","legend":"\u003cp\u003eOnline Resource 2: Video of inguinal lymph node dissection around the fossa ovalis and outside the accessory saphenous vein\u003c/p\u003e","description":"","filename":"OnlineResource2.mp4","url":"https://assets-eu.researchsquare.com/files/rs-1997231/v1/1375bbbecf4b214a6827fc77.mp4"},{"id":25797194,"identity":"cc1441e3-945c-4d6b-8cb8-1868faaf2fb9","added_by":"auto","created_at":"2022-08-29 14:29:44","extension":"mp4","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":70310950,"visible":true,"origin":"","legend":"\u003cp\u003eOnline Resource 3: Video of inguinal lymph node dissection inside the great saphenous vein\u003c/p\u003e","description":"","filename":"OnlineResource3.mp4","url":"https://assets-eu.researchsquare.com/files/rs-1997231/v1/e2bf2f2a25bb29ae71d8ed1e.mp4"}],"financialInterests":"No competing interests reported.","formattedTitle":"Clinical outcomes of neoadjuvant therapy followed by selective inguinal lymph node dissection and total mesorectal excision for metastasised rectal or anal canal adenocarcinoma","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe frequency of metastasis to the inguinal lymph nodes in advanced rectal or anal canal adenocarcinoma is 0.3\u0026ndash;6%, depending on the tumor depth and dentate line involvement [\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However, the treatment strategy for rectal or anal canal adenocarcinoma with inguinal lymph node metastasis (ILNM) has not yet been established.\u003c/p\u003e \u003cp\u003eAccording to reports prior to 2000, rectal or anal adenocarcinoma with ILNM had an extremely poor prognosis, and palliative chemotherapy was recommended [\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. With the advancements in preoperative imaging [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], perioperative treatments [\u003cspan additionalcitationids=\"CR11 CR12 CR13\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], chemotherapy after recurrence [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], and the development of surgical techniques [\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], the treatment outcomes of rectal adenocarcinoma have improved over the past two decades. Recent reports have shown an improved 5-year survival rate of 40\u0026ndash;60% for primary rectal cancer patients with solitary ILNM [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePreoperative treatment is important in terms of local control in the treatment of advanced rectal adenocarcinoma without ILNM; unfortunately, there are only limited reports on preoperative treatment in rectal or anal adenocarcinoma with ILNM. Furthermore, there is a lack of reports on surgical techniques for inguinal lymph node dissection, including the extent of dissection and how to perform it.\u003c/p\u003e \u003cp\u003eIn this study, we demonstrated our standard surgical technique for inguinal lymph node dissection with \u003cem\u003een bloc\u003c/em\u003e resection of the superficial inguinal lymph nodes. Owing to the high frequency of lymphatic leakage after inguinal lymph node dissection, prophylactic bilateral dissection was not performed; instead it was performed only on the side where metastasis was suspected on preoperative imaging. We hope that our short- and long-term results will provide a better understanding of treatment strategies for rectal or anal adenocarcinoma with clinically suspected ILNM.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients\u003c/h2\u003e \u003cp\u003eThis was a single-center, retrospective study of 15 patients with rectal or anal adenocarcinoma associated with suspected ILNM on preoperative imaging. Since 2005, our institution has been performing chest and abdominal computed tomography (CT) scans for patients with advanced lower rectal or anal adenocarcinoma, and if there are no contraindications, abdominal contrast-enhanced CT and positron emission tomography (PET)-CT/ magnetic resonance imaging (MRI) examinations have been performed. Prior to treatment, two or more radiologists were consulted for ILNM diagnosis, and a conference consisting of gastrointestinal surgeons, gastroenterologists, and radiologists made the final determination of clinical metastasis.\u003c/p\u003e \u003cp\u003eILNM has no strict definition; however, a short lymph node diameter of 1 cm or more, an abnormal shape, and an abnormal accumulation of fluorodeoxyglucose(FDG) were defined as clinically positive for metastasis. The definition of the anal canal and rectal adenocarcinoma was based on the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma. Briefly, those tumors with their center above the superior border of the puborectal sling were considered as rectal adenocarcinoma, and those below were considered as anal canal adenocarcinoma.\u003c/p\u003e \u003cp\u003ePatients with concurrent advanced cancer in other sites were excluded from this study. Patients who underwent curative resection for rectal or anal canal adenocarcinoma with clinical ILNM at Kobe University Hospital between 2005 and 2019 were included in this study. This retrospective study was approved by the Institutional Ethics Review Board of the Kobe University Hospital (IRB reference number: B210222).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eNeoadjuvant treatment\u003c/h2\u003e \u003cp\u003eChemoradiotherapy was administered unless radiation was contraindicated or the patient requested chemotherapy. Patients received chemoradiotherapy before surgery with a combination of oral 5FU (capecitabine or tegafur-uracil (UFT)/leucovorin (LV)) and 45\u0026ndash;50.4 Gy of radiation. Patients with contraindications to radiation therapy and those who requested chemotherapy were administered chemotherapy, and the regimen was based on the patient's age, general condition, and preference. One patient who was referred to our hospital after chemoradiation therapy at another institution received additional chemotherapy followed by radical surgery. Radical surgery was performed 5\u0026ndash;8 weeks after chemoradiation therapy or 2\u0026ndash;8 weeks after chemotherapy.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eSurgical procedure\u003c/h2\u003e \u003cp\u003eIf the distance between the lower margin of the tumor and dentate line\u0026thinsp;\u0026gt;\u0026thinsp;2 cm and a distal margin could be maintained, then a low anterior resection was performed. If the distance between the lower margin of the tumor and dentate line was \u0026lt;\u0026thinsp;2 cm, then an abdominoperineal resection was performed. Total pelvic exenteration was performed if there was vaginal, bladder, or prostate involvement. If metastasis was suspected in the lateral pelvic lymph nodes on preoperative imaging, subsequent lateral lymph node dissection was performed. Inguinal lymph node dissection was performed before total mesorectal excision (TME) and lateral lymph node dissection.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eInguinal Lymph Node Dissection\u003c/h2\u003e \u003cp\u003eDue consideration was given to ensure resection of the suspected metastatic lymph nodes by resecting them together with the surrounding fatty tissue. Therefore, the extent of resection varied slightly depending on the degree of inguinal metastasis. The basic surgical technique is as follows: First, a 10\u0026ndash;12 cm skin incision was made in the cephalocaudal direction, subcutaneous fat was incised with an electrocautery scalpel, and a skin flap was made in the medial and lateral directions after the incision of the superficial fascia. While ligating and dissecting the blood vessels and lymphatics, the external oblique aponeurosis was exposed to a cephalad, which was the cephalic end of the dissection (Online Resource 1). The fat was subsequently removed including the inguinal lymph nodes to expose the fascia lata laterally and the accessory saphenous vein caudally, followed by exposure of the fascia lata and fossa ovalis. The blood vessels and lymphatic vessels that pass between the fossa ovalis and the inguinal fat were ligated and dissected to prevent postoperative lymph leakage (Online Resource 2). Finally, the great saphenous vein was exposed, and the fat inside this vein was removed from the caudad to the cephalad to expose the fascia lata (Online Resource 3). We have presented a photograph and anatomical diagram of the post inguinal dissection (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eFollow-up after surgery\u003c/h2\u003e \u003cp\u003eFollow-up was done every 3 months for the first 5 years and every 6 months thereafter. Serum CEA and CA19-9 were measured every 3 months as tumor markers. A thoracoabdominal CT scan was performed every 6 months. If anastomosis was performed, colonoscopy was performed at 1, 2, 3, and 5 years postoperatively. If metastasis was suspected by tumor markers or thoracoabdominal CT scan, then PET or MRI was performed. Local recurrence was defined as recurrence in the pelvis.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed using JMP version 10 (SAS Institute Inc., Cary, NC, USA). Continuous variables were represented with median and range. Survival analysis was performed using the Kaplan-Meier method.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv class=\"Section2\" id=\"Sec10\"\u003e\n \u003ch2\u003ePatient characteristics\u003c/h2\u003e\n \u003cp\u003eOut of the 15 cases, four had anal canal adenocarcinoma and the remaining patients had rectal adenocarcinoma. Demographic and clinical characteristics are shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. The median age of patients was 66 years (range: 71\u0026ndash;78). Ten patients (66.7%) had dentate line involvement, and the distance between the tumor and dentate line was within 5 cm in the other five patients. Eleven patients (73.3%) were treated with preoperative chemoradiotherapy as neoadjuvant therapy. Three patients were treated with preoperative chemotherapy, including one patient who received seven courses of FOLFOX plus bevacizumab at his request, one patient who received six courses of FOLFOXIRI plus bevacizumab at his request, and one patient who received six courses of FOLFOX because she had previously been treated with radiation therapy for uterine cancer and could not receive chemoradiation. One patient was referred after preoperative chemoradiotherapy at another hospital and was operated on after seven courses of FOLFOX plus cetuximab.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable border=\"1\" id=\"Tab1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDemographic and clinical characteristics\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCharacteristics\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCase (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGender\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(53.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(46.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge, y\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMedian (range)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(41\u0026ndash;78)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eASA class\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eASA 1\u0026ndash;2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(93.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eASA\u0026thinsp;\u0026gt;\u0026thinsp;2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(6.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDistance from the anal verge, cm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMedian (range)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(0\u0026ndash;5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eClinical tumor stage\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(6.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(26.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(66.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eClinical nodal stage\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(13.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(86.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNeoadjuvant therapy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(73.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT followed by CT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(6.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\"\u003e\u003csup\u003ea\u003c/sup\u003eTumor were classified according to the eighth edition of the Union for International Cancer Control tumor-node-metastasis cancer staging system.\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\"\u003eData are presented as n (%)\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\"\u003e\u003cem\u003eASA\u003c/em\u003e, American Society of Anesthesiologists; \u003cem\u003eCRT\u003c/em\u003e, chemoradiotherapy; \u003cem\u003eCT\u003c/em\u003e, chemotherapy.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec11\"\u003e\n \u003ch2\u003eOperative outcomes and pathological findings\u003c/h2\u003e\n \u003cp\u003eOperative outcomes and pathological findings are listed in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. Unilateral inguinal dissection was performed in six patients and bilateral inguinal dissection in nine patients. Seven patients (43.8%) had inguinal seroma of Clavien-dindo classification Grade 2 or higher. Reoperation for inguinal seroma was necessary in three cases (20.0%); lymphatic ligation was performed in two cases, and drainage was performed in one case because of infection. Preoperative treatment resulted in a marked effect in three patients (20.0%). Two patients had positive circumferential resection margins.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable border=\"1\" id=\"Tab2\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eOperative and pathological outcomes\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCharacteristics\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCase (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eApproach\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOpen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(40.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLaparoscopic\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(60.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSurgical procedure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLow anterior resection\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAbdominoperineal resection\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(66.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTotal pelvic exenteration\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(13.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003ePostoperative complications, Clavient-dindo classification grade≧Ⅱ\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eInguinal seroma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(46.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSuperficial wound infection\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(33.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIntra-pelvic abscess\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(6.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSmall bowel obstruction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(6.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHistology\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWell/moderately differentiated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(86.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePoorly differentiated/mucinous\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(13.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePathological tumor stage\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(26.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(33.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePathological nodal stage\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(53.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(26.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eProximal resection margin positive\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDistal resection margin positive\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCircumferential resection margin positive\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(13.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\"\u003e\u003csup\u003ea\u003c/sup\u003e Tumor were classified according to the eighth edition of the Union for International Cancer Control tumor-node-metastasis cancer staging system\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec12\"\u003e\n \u003ch2\u003eFluorodeoxyglucose accumulation in the inguinal region\u003c/h2\u003e\n \u003cp\u003eFDG-PET scans were performed after neoadjuvant therapy in 14 patients (93.3%). One patient who did not undergo an FDG-PET scan after preoperative treatment underwent an FDG-PET scan before neoadjuvant therapy, and no FDG accumulation was observed in that case. Six patients had negative FDG accumulation in the inguinal lymph nodes on preoperative FDG-PET scan, and their inguinal lymph nodes were also pathologically negative for metastasis. Of the nine patients who had positive FDG accumulation, four (44.4%) had pathologically positive ILNM (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable border=\"1\" id=\"Tab3\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eNeoadjuvant treatment, preoperative fluorodeoxyglucose PET-CT/MRI findings, pathological findings, and long-term outcomes\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eAge\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSex\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eNeoadjuvant treatment\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eBefore neoadjuvant therapy\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eAfter neoadjuvant therapy\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eILN dissection\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003ePathological findings\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSite of recurrence/ interval from treatment to recurrence\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eOutcome/ follow-up\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMaximum size of ILN (mm)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSUVmax/ clinical diagnosis\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMaximum size of ILN (mm)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSUVmax/\u003c/p\u003e\n \u003cp\u003eclinical diagnosis\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNumber of metastatic ILN\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNumber of ILN harvested\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003epT stage\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003epN stage\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eResponse to chemotherapy or radiation\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.12/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLocal/6y0m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/8y10m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT followed by CT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.13/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 1b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLocal /1y0m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/3y4m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.31/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.58/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 1b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo /7y1m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/7y1m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.49/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.49/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLung /1y1m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDied/3y10m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.86/ N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo/16y7m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/16y7m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.22/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.71/ N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo/9y11m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/9y11m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.72/ N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo/8y7m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/8y7m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.72/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.87/ N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo/5y6m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/5y6m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.46/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.52/ N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo/3y0m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/3y0m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14.60/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.84/ N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo/2y4m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/2y4m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.60/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.12/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 1b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo/8y6m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/8y6m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.95/ N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.12/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo/4y1m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/4y1m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.97/ N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.95/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 1b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLocal/4y6m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlive/5y3m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCRT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.04/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.68/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 1b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLocal/7m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDied/2y7m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.14/ P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGrade 1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLung /1y0m\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDied/1y6m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"15\"\u003e\u003csup\u003ea\u003c/sup\u003eTumor were classified according to the eighth edition of the Union for International Cancer Control tumor-node-metastasis cancer staging system.\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"15\"\u003e\u003csup\u003eb\u003c/sup\u003e Histological criteria of primary rectal cancer for the assessment of response to chemotherapy or radiation were classified according to the 3rd English edition of the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma [\u003cspan class=\"CitationRef\"\u003e26\u003c/span\u003e]: Grade 0 (No effect), Grade 1a (Minimal effect: Tumor cell change\u0026thinsp;\u0026lt;\u0026thinsp;1/3), Grade 1b (Mild effect: Tumor cell change\u0026thinsp;\u0026lt;\u0026thinsp;2/3), Grade 2 (Moderate effect: Tumor cell change\u0026thinsp;\u0026gt;\u0026thinsp;2/3), Grade 3 (Marked effect: No viable tumor cells are observed)\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"15\"\u003e\u003cem\u003eM\u003c/em\u003e, male; \u003cem\u003eF\u003c/em\u003e, female; \u003cem\u003eILN\u003c/em\u003e, inguinal lymph node; \u003cem\u003eSUVmax\u003c/em\u003e, the maximum standardized uptake value; \u003cem\u003eP\u003c/em\u003e, positive; \u003cem\u003eN\u003c/em\u003e, negative; \u003cem\u003eB\u003c/em\u003e, bilateral; \u003cem\u003eU\u003c/em\u003e, unilateral; \u003cem\u003eCRT\u003c/em\u003e, chemoradiotherapy; \u003cem\u003eCT\u003c/em\u003e, chemotherapy; \u003cem\u003ePET-CT/MRI\u003c/em\u003e, positron emission tomography/ magnetic resonance image\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec13\"\u003e\n \u003ch2\u003eAdjuvant therapy\u003c/h2\u003e\n \u003cp\u003eNine patients (66.7%) received postoperative adjuvant chemotherapy. Three patients received 5FU/LV, two received FOLFOX therapy and four received CapeOX therapy.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec14\"\u003e\n \u003ch2\u003eLong-term outcomes\u003c/h2\u003e\n \u003cp\u003eThe median follow-up period was 63 months. The 3- and 5-year overall survival rates were 86.2% and 77.5%, respectively. The 3- and 5-year recurrence-free survival rates were 73.3% and 64.2%, respectively (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eRectal or anal canal adenocarcinoma with ILNM is rare, and is often encountered clinically and the treatment strategy is challenging. Systemic chemotherapy is recommended for patients with unresectable distant metastasis; however, no clear treatment strategy has been established for patients with resectable distant metastasis or no metastasis other than ILNM. There are no prospective clinical studies in patients with rectal or anal canal adenocarcinoma with only ILMN; only retrospective studies in a small number of cases have been reported. While long-term survival of more than 5 years was extremely rare in reports prior to 2000 [\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], recent reports have reported 5-year survival rates of 15.9\u0026ndash;55.2% [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan additionalcitationids=\"CR21 CR22 CR23\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. This study had the highest number of cases of radical resection for simultaneous metastases and the most favorable outcomes among papers reporting 5-year overall survival rates of 50% or greater [\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eLymph node metastasis of rectal or anal canal adenocarcinoma often occurs in the mesorectum, and total mesorectal excision is the foremost procedure in the treatment of rectal or anal canal adenocarcinoma. However, lymph node metastasis of rectal or anal canal adenocarcinoma can also extend beyond the mesorectum, with typical examples being para-aortic lymph node metastasis, lateral lymph node metastasis, and inguinal lymph node metastasis. The 5-year recurrence-free survival rate for lymph node dissection for para-aortic lymph node metastases is about 15%, with limited efficacy [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Lateral lymph node dissection for lateral lymph node metastases is considered effective and has been reported to reduce local recurrence in a randomized controlled trial (RCT) [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Inguinal lymph node dissection for inguinal lymph node metastases has exhibited good results in some studies [\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], including in this study, and may potentially be effective.\u003c/p\u003e \u003cp\u003eThe common technique for dissecting the inguinal lymph nodes for rectal or anal canal adenocarcinoma is to dissect the shallow inguinal lymph nodes, but the extent of dissection has not been established. We considered it important to resect lymph nodes suspected of metastasis along with surrounding fat after neoadjuvant therapy. The fascia lata, fossa ovalis, accessory saphenous vein, and great saphenous vein are good anatomical landmarks for inguinal lymph node dissection.\u003c/p\u003e \u003cp\u003eFew reports mentioned inguinal seroma after inguinal dissection for rectal cancer, and one study reported it in four of 17 patients (23.5%) who underwent inguinal lymph node dissection [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In another study of 240 patients who underwent inguinal dissection for malignant melanoma, 51.2% had wound complications and 21.5% had seroma [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. In this study, seven of 15 patients (43.8%) who underwent inguinal lymph node dissection had inguinal seroma, and three (20%) required reoperation, which was relatively a high complication rate. Although the frequency of inguinal seroma varies depending on the extent of lymph node dissection and the definition of the complication, postoperative inguinal seroma is an important complication after inguinal lymph node dissection and may be the cause of hesitation to dissect.\u003c/p\u003e \u003cp\u003eThe indications for preoperative treatment of rectal cancer with ILMN may require further investigation. Results of several RCTs have indicated that chemoradiotherapy improved local control [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] and total neoadjuvant therapy improved disease-free survival [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]; however, there is no clear evidence of overall survival improvement. There is a report signifying a 55.2% 5-year survival rate after radical surgery without neoadjuvant treatment for rectal cancer with ILMN. In this study, all patients were treated preoperatively, and no pathologic inguinal lymph node metastasis was observed in patients with negative FDG uptake in the inguinal region after neoadjuvant therapy. Therefore, inguinal lymph node dissection may be omitted in cases in which FDG uptake is negative after neoadjuvant therapy.\u003c/p\u003e \u003cp\u003eThere are several limitations in this study. First, this was a retrospective study that may include bias. Second, the inguinal lymph node metastasis may be over-estimated because it was determined clinically rather than pathologically. However, we felt that a clinical diagnosis was appropriate, as a preoperative needle biopsy was not easy to perform because of the proximity of important blood vessels in the inguinal region, and an exploratory biopsy could obscure the anatomy at the time of inguinal lymph node dissection. Third, this study did not include patients with resectable distant metastases in the liver or lungs other than the inguinal lymph nodes; hence, it was not possible to demonstrate what treatment would be best in these patients. Fourth, this was a single-center study with a small number of cases.\u003c/p\u003e \u003cp\u003eTo conclude, radical surgery including inguinal lymph node dissection after adjuvant therapy has demonstrated a better long-term prognosis in patients with rectal or anal canal adenocarcinoma associated with ILNM, although a high rate of inguinal seroma was observed.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by Japan Society for the Promortion of Science KAKENHI (grant number 21K16446).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no competing interests to declare that are relevant to the content of this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Institutional Ethics Review Board of the Kobe University Hospital (reference number: B210222; |Date of approval|).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed Consent:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical approval was waived by the Institutional Ethics Review Board of the Kobe University Hospital in view of the retrospective nature of the study and all the procedures being performed were part of the routine care.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability statement:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study can be made available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; Contribution:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Hiroshi Hasegawa, Takeru Matsuda, Kimihiro Yamashita and Ryuichiro Sawada. The first draft of the manuscript was written by Hiroshi Hasegawa and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by Japan Society for the Promortion of Science KAKENHI (grant number 21K16446).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHamano T, Homma Y, Otsuki Y, Shimizu S, Kobayashi H, Kobayashi Y (2010) Inguinal lymph node metastases are recognized with high frequency in rectal adenocarcinoma invading the dentate line. The histological features at the invasive front may predict inguinal lymph node metastasis. Colorectal Dis 12:e200\u0026ndash;e205. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/j.1463-1318.2009.02134.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1463-1318.2009.02134.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShiratori H, Nozawa H, Kawai K, et al (2020) Risk factors and therapeutic significance of inguinal lymph node metastasis in advanced lower rectal cancer. Int J Colorectal Dis 35:655\u0026ndash;664. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00384-020-03520-2\u003c/span\u003e\u003cspan address=\"10.1007/s00384-020-03520-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang R, Wu P, Shi D, et al (2014) Risk factors of synchronous inguinal lymph nodes metastasis for lower rectal cancer involving the anal canal. PLoS One 9:e111770. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pone.0111770\u003c/span\u003e\u003cspan address=\"10.1371/journal.pone.0111770\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSaiki Y, Yamada K, Tanaka M, Fukunaga M, Irei Y, Suzuki T (2022) Prognosis of anal canal adenocarcinoma versus lower rectal adenocarcinoma in Japan: a propensity score matching study. Surg Today 52:420\u0026ndash;430. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00595-021-02350-1\u003c/span\u003e\u003cspan address=\"10.1007/s00595-021-02350-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLuna-P\u0026eacute;rez P, Corral P, Labastida S, Rodr\u0026iacute;guez-Coria D, Delgado S (1999) Inguinal lymph node metastases from rectal adenocarcinoma. J Surg Oncol 70:177\u0026ndash;180. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1002/(sici)1096-9098(199903)70:3\u0026lt;177::aid-jso6\u0026gt;3.0.co;2-0\u003c/span\u003e\u003cspan address=\"10.1002/(sici)1096-9098(199903)70:3%3C177::aid-jso6%3E3.0.co;2-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTocchi A, Lepre L, Costa G, et al (1999) Rectal cancer and inguinal metastases: prognostic role and therapeutic indications. Dis Colon Rectum 42:1464\u0026ndash;1466. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/BF02235048\u003c/span\u003e\u003cspan address=\"10.1007/BF02235048\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMesko TW, Rodriguez-Bigas MA, Petrelli NJ (1994) Inguinal lymph node metastases from adenocarcinoma of the rectum. Am J Surg 168:285\u0026ndash;287. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/s0002-9610(05)80204-1\u003c/span\u003e\u003cspan address=\"10.1016/s0002-9610(05)80204-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCaruso R, Vicente E, Quijano Y, et al (2021) Role of 18F-PET-CT to predict pathological response after neoadjuvant treatment of rectal cancer. Discov Oncol 12:16. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s12672-021-00405-w\u003c/span\u003e\u003cspan address=\"10.1007/s12672-021-00405-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUemura M, Ikeda M, Handa R, et al (2021) The efficiency of 18F-FDG-PET/CT in the assessment of tumor response to preoperative chemoradiation therapy for locally recurrent rectal cancer. BMC Cancer 21:1132. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s12885-021-08873-7\u003c/span\u003e\u003cspan address=\"10.1186/s12885-021-08873-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eConroy T, Bosset JF, Etienne PL, et al (2021) Neoadjuvant chemotherapy with FOLFIRINOX and preoperative chemoradiotherapy for patients with locally advanced rectal cancer (UNICANCER-PRODIGE 23): a multicentre, randomised, open-label, phase 3 trial. Lancet Oncol 22:702\u0026ndash;715. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S1470-2045(21)00079-6\u003c/span\u003e\u003cspan address=\"10.1016/S1470-2045(21)00079-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBosset JF, Collette L, Calais G, et al (2006) Chemotherapy with preoperative radiotherapy in rectal cancer. N Engl J Med 355:1114\u0026ndash;1123. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1056/NEJMoa060829\u003c/span\u003e\u003cspan address=\"10.1056/NEJMoa060829\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBahadoer RR, Dijkstra EA, van Etten B, et al (2021) Short-course radiotherapy followed by chemotherapy before total mesorectal excision (TME) versus preoperative chemoradiotherapy, TME, and optional adjuvant chemotherapy in locally advanced rectal cancer (RAPIDO): a randomised, open-label, phase 3 trial. Lancet Oncol 22:29\u0026ndash;42. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S1470-2045(20)30555-6\u003c/span\u003e\u003cspan address=\"10.1016/S1470-2045(20)30555-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChakravarthy AB, Zhao F, Meropol NJ, et al (2020) Intergroup randomized Phase III study of postoperative oxaliplatin, 5-fluorouracil, and leucovorin versus oxaliplatin, 5-fluorouracil, leucovorin, and bevacizumab for patients with Stage II or III rectal cancer receiving preoperative chemoradiation: a trial of the ECOG-ACRIN research group (E5204). Oncologist 25:e798\u0026ndash;e807. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1634/theoncologist.2019-0437\u003c/span\u003e\u003cspan address=\"10.1634/theoncologist.2019-0437\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHong YS, Nam BH, Kim KP, et al (2014) Oxaliplatin, fluorouracil, and leucovorin versus fluorouracil and leucovorin as adjuvant chemotherapy for locally advanced rectal cancer after preoperative chemoradiotherapy (ADORE): an open-label, multicentre, phase 2, randomised controlled trial. Lancet Oncol 15:1245\u0026ndash;1253. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S1470-2045(14)70377-8\u003c/span\u003e\u003cspan address=\"10.1016/S1470-2045(14)70377-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTabernero J, Grothey A, Van Cutsem E, et al (2021) Encorafenib plus cetuximab as a new standard of care for previously treated BRAF V600E-mutant metastatic colorectal cancer: updated survival results and subgroup analyses from the Beacon study. J Clin Oncol 39:273\u0026ndash;284. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1200/JCO.20.02088\u003c/span\u003e\u003cspan address=\"10.1200/JCO.20.02088\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLoupakis F, Cremolini C, Masi G, et al (2014) Initial therapy with FOLFOXIRI and bevacizumab for metastatic colorectal cancer. N Engl J Med 371:1609\u0026ndash;1618. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1056/NEJMoa1403108\u003c/span\u003e\u003cspan address=\"10.1056/NEJMoa1403108\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFujita S, Mizusawa J, Kanemitsu Y, et al (2017) Mesorectal excision with or without lateral lymph node dissection for clinical Stage II/III lower rectal cancer (JCOG0212): A multicenter, randomized controlled, noninferiority trial. Ann Surg 266:201\u0026ndash;207. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/SLA.0000000000002212\u003c/span\u003e\u003cspan address=\"10.1097/SLA.0000000000002212\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHeald RJ, Husband EM, Ryall RD (1982) The mesorectum in rectal cancer surgery\u0026ndash;the clue to pelvic recurrence? Br J Surg 69:613\u0026ndash;616. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1002/bjs.1800691019\u003c/span\u003e\u003cspan address=\"10.1002/bjs.1800691019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMacFarlane JK, Ryall RD, Heald RJ (1993) Mesorectal excision for rectal cancer. Lancet 341:457\u0026ndash;460. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0140-6736(93)90207-w\u003c/span\u003e\u003cspan address=\"10.1016/0140-6736(93)90207-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHagemans JAW, Rothbarth J, van Bogerijen GHW, et al (2019) Treatment of inguinal lymph node metastases in patients with rectal adenocarcinoma. Ann Surg Oncol 26:1134\u0026ndash;1141. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1245/s10434-019-07191-4\u003c/span\u003e\u003cspan address=\"10.1245/s10434-019-07191-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTanabe T, Shida D, Komukai S, Nakamura Y, Tsukamoto S, Kanemitsu Y (2019) Long-term outcomes after surgical dissection of inguinal lymph node metastasis from rectal or anal canal adenocarcinoma. BMC Cancer 19:733. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s12885-019-5956-y\u003c/span\u003e\u003cspan address=\"10.1186/s12885-019-5956-y\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbd El Aziz MA, McKenna NP, Jakub JW, et al (2022) Rectal cancer with synchronous inguinal lymph node metastasis without distant metastasis. A call for further oncological evaluation. Eur J Surg Oncol 48:1100\u0026ndash;1103. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.ejso.2021.12.018\u003c/span\u003e\u003cspan address=\"10.1016/j.ejso.2021.12.018\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAdachi T, Hinoi T, Egi H, Ohdan H (2013) Surgical treatment for isolated inguinal lymph node metastasis in lower rectal adenocarcinoma patients improves outcome. Int J Colorectal Dis 28:1675\u0026ndash;1680. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00384-013-1746-1\u003c/span\u003e\u003cspan address=\"10.1007/s00384-013-1746-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSu Z, Guo ZW, Mao YP, et al (2017) Anal adenocarcinoma requires prophylactic inguinal nodal treatment: results from a single Chinese institution. J Cancer 8:1097\u0026ndash;1102. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.7150/jca.17513\u003c/span\u003e\u003cspan address=\"10.7150/jca.17513\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSakamoto J, Ozawa H, Nakanishi H, Fujita S (2020) Oncologic outcomes after resection of para-aortic lymph node metastasis in left-sided colon and rectal cancer. PLoS One 15:e0241815. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pone.0241815\u003c/span\u003e\u003cspan address=\"10.1371/journal.pone.0241815\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNakai N, Yamaguchi T, Kinugasa Y, et al (2017) Long-term outcomes after resection of para-aortic lymph node metastasis from left-sided colon and rectal cancer. Int J Colorectal Dis 32:999\u0026ndash;1007. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00384-017-2806-8\u003c/span\u003e\u003cspan address=\"10.1007/s00384-017-2806-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFaut M, Heidema RM, Hoekstra HJ, et al (2017) Morbidity after inguinal lymph node dissections: it is time for a change. Ann Surg Oncol 24:330\u0026ndash;339. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1245/s10434-016-5461-3\u003c/span\u003e\u003cspan address=\"10.1245/s10434-016-5461-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003evan Gijn W, Marijnen CA, Nagtegaal ID, et al (2011) Preoperative radiotherapy combined with total mesorectal excision for resectable rectal cancer: 12-year follow-up of the multicentre, randomised controlled TME trial. Lancet Oncol 12:575\u0026ndash;582. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S1470-2045(11)70097-3\u003c/span\u003e\u003cspan address=\"10.1016/S1470-2045(11)70097-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"langenbecks-archives-of-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"laos","sideBox":"Learn more about [Langenbeck's Archives of Surgery](http://link.springer.com/journal/423)","snPcode":"423","submissionUrl":"https://submission.nature.com/new-submission/423/3","title":"Langenbeck's Archives of Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Rectal cancer, anal cancer, adenocarcinoma, inguinal lymph node dissection, neoadjuavnt therapy, metastasis","lastPublishedDoi":"10.21203/rs.3.rs-1997231/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1997231/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eRectal or anal canal adenocarcinoma with inguinal lymph node metastasis (ILNM) is rare and is associated with poor prognostic outcomes. This study aimed to elucidate the clinical significance of neoadjuvant therapy followed by selective inguinal lymph node dissection and total mesorectal excision for rectal or anal canal adenocarcinoma with clinically suspected ILNM.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis study enrolled 15 consecutive patients who underwent neoadjuvant therapy and curative resection for rectal or anal canal adenocarcinoma with clinically suspected ILNM between 2005 and 2019 at a single institution. Inguinal lymph node dissection was selectively performed on the side of suspected metastasis before neoadjuvant therapy. Short- and long-term outcomes were retrospectively reviewed.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eOut of the15 patients, 11 were treated with neoadjuvant chemoradiation, three with chemotherapy, and one with chemoradiation followed by chemotherapy. Six patients had negative fluorodeoxyglucose (FDG) accumulation in inguinal lymph nodes on preoperative FDG-positron emission tomography (FDG-PET) scan, and their inguinal lymph nodes were also pathologically negative for metastasis. Of the nine patients who had positive FDG accumulation, four had pathologically positive inguinal lymph nodes. Seven patients (46.7%) had inguinal seroma postoperatively. Five-year-overall survival was 77.5%, and 5-year-relapse-free survival was 64.2%. No patient had a recurrence in the inguinal region.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eIn patients with rectal or anal canal adenocarcinoma associated with clinical ILNM, radical resection with neoadjuvant therapy provides a good long-term survival.\u003c/p\u003e","manuscriptTitle":"Clinical outcomes of neoadjuvant therapy followed by selective inguinal lymph node dissection and total mesorectal excision for metastasised rectal or anal canal adenocarcinoma","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-08-29 14:29:39","doi":"10.21203/rs.3.rs-1997231/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2022-10-13T08:10:54+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-09-22T16:08:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"26ab0d25-9878-47e0-b343-2e70f430240b","date":"2022-09-10T23:22:05+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-09-10T22:22:56+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-08-26T09:58:17+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-08-25T11:20:25+00:00","index":"","fulltext":""},{"type":"submitted","content":"Langenbeck's Archives of Surgery","date":"2022-08-25T09:35:51+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"langenbecks-archives-of-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"laos","sideBox":"Learn more about [Langenbeck's Archives of Surgery](http://link.springer.com/journal/423)","snPcode":"423","submissionUrl":"https://submission.nature.com/new-submission/423/3","title":"Langenbeck's Archives of Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"67ae8ecc-3589-479f-86e4-f71250c68ab7","owner":[],"postedDate":"August 29th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T18:09:54+00:00","versionOfRecord":{"articleIdentity":"rs-1997231","link":"https://doi.org/10.1007/s00423-022-02739-7","journal":{"identity":"langenbecks-archives-of-surgery","isVorOnly":false,"title":"Langenbeck's Archives of Surgery"},"publishedOn":"2022-12-28 18:07:35","publishedOnDateReadable":"December 28th, 2022"},"versionCreatedAt":"2022-08-29 14:29:39","video":"","vorDoi":"10.1007/s00423-022-02739-7","vorDoiUrl":"https://doi.org/10.1007/s00423-022-02739-7","workflowStages":[]},"version":"v1","identity":"rs-1997231","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1997231","identity":"rs-1997231","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}