Lymph Node Distribution Patterns and Oncologic Outcomes: A Propensity Score-Matched Retrospective Comparison of Right Hemicolectomy versus Ileocecal Resection in Stage III Right-Sided Colon Cancer

Lymph Node Distribution Patterns and Oncologic Outcomes: A Propensity Score-Matched Retrospective Comparison of Right Hemicolectomy versus Ileocecal Resection in Stage III Right-Sided Colon Cancer | 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 Lymph Node Distribution Patterns and Oncologic Outcomes: A Propensity Score-Matched Retrospective Comparison of Right Hemicolectomy versus Ileocecal Resection in Stage III Right-Sided Colon Cancer Bolun Song, Liming Wang, Yinggang Chen, Yasumitsu Hirano² This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8757786/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Right hemicolectomy (RHC) and ileocecal resection (ICR) are two widely used surgical approaches for right-sided colon cancer. However, controversies persist regarding their differences in lymph node (LN) dissection completeness, LN metastasis patterns, and long-term oncologic outcomes in patients with stage III disease. This study aimed to compare LN distribution, surgical outcomes, and survival profiles between RHC and ICR in patients with stage III right-sided colon cancer. Methods A retrospective analysis was conducted on patients with primary right-sided colon cancer who underwent RHC or ICR at a large oncology center in Japan. Propensity score matching (PSM) was applied to balance baseline characteristics between the two groups at a 1:1 ratio. Comparisons were made regarding LN metastasis rates at different stations (pericolic, intermediate, and apical LNs), surgical outcomes, 5-year overall survival (OS), cancer-specific survival (CSS), relapse-free survival (RFS), and recurrence patterns. Results A total of 216 patients in the RHC group and 223 patients in the ICR group were enrolled. After PSM, 185 patients were included in each group. The mean number of excised lymph nodes was significantly higher in the RHC group than in the ICR group both before (36.0 ± 15.0 vs. 26.4 ± 10.6, p < 0.001) and after PSM (36.0 ± 13.8 vs. 26.0 ± 10.7, p < 0.001). The D1 nodal metastasis rate was significantly lower in the RHC group both before (13.9% vs. 4.0%, p < 0.001) and after PSM (13.0% vs. 4.3%, p = 0.005). No significant differences were observed in 5-year OS (70.8% vs. 62.7%, p = 0.137), CSS (77.4% vs. 69.4%, p = 0.190), or RFS (72.2% vs. 71.4%, p = 0.526) between the two groups after PSM. Multivariate logistic regression analysis revealed that histology type (poorly differentiated, signet ring, or mucinous carcinoma), venous invasion, and pN stage were independent prognostic factors for OS, while pN stage was an independent prognostic factor for RFS. A high carcinoembryonic antigen (CEA) level was identified as a common independent high-risk factor for OS, CSS, and RFS. Recurrence patterns (involving the liver, lung, lymph nodes, peritoneum, etc.) were similar between the two groups (all non-significant [N.S]). Conclusion For stage III right-sided colon cancer, RHC achieves a higher number of excised lymph nodes compared with ICR. However, the number of metastatic lymph nodes does not differ significantly between the two groups, and there are no significant differences in long-term oncologic outcomes. The selection of surgical procedure should be individualized based on tumor location, size, and patient-specific factors. Lymph node distribution Stage III right-sided colon cancer Right hemicolectomy Ileocecal resection Propensity score matching Figures Figure 1 Figure 2 Figure 3 Introduction Colorectal cancer (CRC) is one of the most common malignant tumors worldwide, with right-sided colon cancer accounting for approximately 30%–40% of all CRC cases [ 1 , 2 ]. Lymph node metastasis is a key prognostic factor for patients with CRC, and complete lymph node dissection is crucial for accurate staging and improving long-term survival [ 3 , 4 ]. For right-sided colon cancer, the standard surgical procedure is right hemicolectomy (RHC), which involves resection of the ascending colon, cecum, terminal ileum, and associated mesentery, along with complete lymph node dissection[ 5 ]. However, ileocecal resection (ICR), which resects the cecum, ileocecal valve, and a short segment of the terminal ileum and ascending colon, is also widely used in clinical practice, especially for tumors located near the ileocecal valve [ 5 , 6 ]. The controversy surrounding RHC and ICR mainly focuses on whether ICR can achieve equivalent lymph node dissection completeness and oncologic outcomes compared with RHC, especially in stage III right-sided colon cancer. Some studies have shown that ICR is associated with fewer excised lymph nodes and a higher risk of incomplete lymph node dissection, which may compromise staging accuracy and long-term survival[ 7 ]. In contrast, other studies have suggested that ICR can achieve similar oncologic outcomes to RHC for selected patients with right-sided colon cancer, with the advantages of less surgical trauma, shorter operative time, and faster postoperative recovery [ 8 ]. To clarify the differences in lymph node distribution patterns, surgical outcomes, and long-term survival between RHC and ICR in patients with stage III right-sided colon cancer. This study aimed to provide clinical evidence for the rational choice of surgical procedure for stage III right-sided colon cancer. Materials and Methods A retrospective study was conducted at the Division of Gastroenterological Surgery, Saitama Medical University International Medical Center, covering a 13-year period from April 2007 to December 2020. The median follow-up duration was 96 months. The study was approved by the Ethics Committee of the International Medical Center of Saitama Medical University (Ethics Review No. : IRB2023-036), and written informed consent was obtained from all participants. The inclusion criteria were: (1) pathologically confirmed primary right-sided colon cancer (located in the cecum, ascending colon, or hepatic flexure); (2) stage III disease according to the American Joint Committee on Cancer (AJCC) TNM staging system (8th edition); (3) underwent RHC or ICR; (4) complete clinical, surgical, and follow-up data. The exclusion criteria were: (1) multiple malignant tumors; (2) recurrent colon cancer; (3) distant metastasis at diagnosis; (4) underwent total colectomy; (5) no lymph node metastasis; (6) incomplete clinical or follow-up data. All surgical procedures were performed by experienced surgeons in the Division of Gastroenterological Surgery, in accordance with the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma (JCCRC)[ 5 ]. RHC was performed for tumors in the distal ascending colon or hepatic flexure with resection of the terminal ileum (5–10 cm), cecum, ascending colon, hepatic flexure. The procedure involved the resection of the terminal ileum (5–10 cm), cecum, ascending colon, hepatic flexure, and a portion of the transverse colon, along with complete mesocolic excision and central vascular ligation to ensure adequate lymph node dissection (including pericolic, intermediate, and apical lymph nodes). ICR was performed for tumors in the cecum or proximal ascending colon when no blood supply from the right branch of the middle colic artery extended beyond 10 cm distal to the tumor. The procedure involved the resection of the terminal ileum (10 cm), cecum, ileocecal valve, and a 10 cm segment of the ascending colon distal to the tumor, along with lymph node dissection around the ileocolic vessels (including pericolic, intermediate, and apical lymph nodes). Clinical data were collected from the hospital’s electronic medical records, including baseline characteristics (gender, age, body mass index [BMI], carcinoembryonic antigen [CEA] level, tumor family history, abdominal surgery history, comorbidities), surgical parameters (operative method, operative time, operative blood loss, postoperative complications, postoperative hospital stay, time to first food intake, adjuvant chemotherapy), pathological characteristics (tumor size, resection margins, gross type, histology type, infiltration form, lymphatic invasion, venous invasion, number of excised lymph nodes, number of metastatic lymph nodes, pT stage, pN stage, lymph node metastasis at different stations), and follow-up data (survival status, recurrence status, recurrence site). All patients were followed up regularly after surgery. The follow-up schedule was every 3 months for the first 3 years, every 6 months for years 4–5, and annually thereafter. Follow-up examinations included physical examination, blood tests (CEA, CA19-9), abdominal computed tomography (CT), chest CT, and colonoscopy every year. The primary endpoints were 5-year overall survival (OS), 5-year cancer-specific survival (CSS), and 5-year relapse-free survival (RFS). OS was defined as the time from surgery to death from any cause. CSS was defined as the time from surgery to death from colon cancer. RFS was defined as the time from surgery to the first occurrence of local recurrence or distant metastasis. Statistical analysis was performed using SPSS 22.0 software (IBM Corp., Tokyo, Japan). Continuous variables were expressed as mean ± standard deviation (SD) and compared using the t-test or Mann-Whitney U test. Categorical variables were expressed as counts and percentages and compared using the χ² test or Fisher’s exact test. Propensity score matching (PSM) was used to balance baseline characteristics between the RHC and ICR groups at a 1:1 ratio, with a caliper width of 0.2. The variables included in PSM were gender, age, BMI, CEA level, tumor family history, abdominal surgery history, comorbidity, operative method, and pT stage. Survival curves were plotted using the Kaplan-Meier method and compared using the log-rank test. Multivariate logistic regression analysis was used to identify independent prognostic factors for OS, CSS, and RFS. A p-value < 0.05 was considered statistically significant. Results During the study period, a total of 6273 patients with primary colorectal cancer were identified. Among them, 1013 patients had primary right-sided colon cancer, and 146 patients were excluded based on the exclusion criteria (multiple malignant tumors, recurrent cancer, distant metastasis, total colectomy). After excluding patients without lymph node metastasis, 216 patients in the RHC group and 223 patients in the ICR group were enrolled (Fig. 1). After PSM, 185 patients were included in each group, and no significant differences were observed in baseline characteristics between the two groups (all N.S.), indicating that the two groups were well balanced (Table 1). Before PSM, the proportion of laparoscopic surgery was significantly higher in the ICR group than in the RHC group (90.1% vs. 78.7%, p = 0.001), the operative time was significantly shorter in the ICR group (152 ± 58.2 min vs. 193 ± 66.4 min, p < 0.001), and the operative blood loss was significantly less in the ICR group (p < 0.001). There were no significant differences in postoperative complications, postoperative hospital stays, time to first food intake, or adjuvant chemotherapy rate between the two groups (all N.S). After PSM, there were no significant differences in laparoscopic surgery rate, operative blood loss, postoperative complications, postoperative hospital stay, time to first food intake, or adjuvant chemotherapy rate between the two groups (all N.S), but the operative time was still significantly shorter in the ICR group than in the RHC group (149 ± 60.0 min vs. 189 ± 61.1 min, p < 0.001) (Table 1). Before PSM, the mean tumor size was significantly larger in the RHC group than in the ICR group (5.39 ± 2.59 cm vs. 4.90 ± 2.28 cm, p = 0.037), the mean proximal resection margin was significantly longer in the RHC group (14.5 ± 6.52 cm vs. 11.9 ± 5.88 cm, p < 0.001), the mean number of excised lymph nodes was significantly higher in the RHC group (36.0 ± 15.0 vs. 26.4 ± 10.6, p < 0.001), the pT stage distribution was significantly different between the two groups (p = 0.019), and the pN stage distribution was significantly different between the two groups (p = 0.026). The D1 nodal metastasis rate was significantly lower in the RHC group than in the ICR group (86.1% vs. 96.0%, p < 0.001). There were no significant differences in distal resection margin, gross type, histology type, infiltration form, lymphatic invasion, venous invasion, or number of metastatic lymph nodes between the two groups (all N.S). After PSM, there were no significant differences in tumor size, pT stage, pN stage, or other pathological characteristics between the two groups (all N.S), except that the mean proximal resection margin was still significantly longer in the RHC group than in the ICR group (14.3 ± 6.48 cm vs. 12.0 ± 6.16 cm, p < 0.001), and the mean number of excised lymph nodes was still significantly higher in the RHC group than in the ICR group (36.0 ± 13.8 vs. 26.0 ± 10.7, p < 0.001). The D1 nodal metastasis rate was still significantly lower in the RHC group than in the ICR group (87.0% vs.95.7%, p = 0.005) (Table 2). The lymph node metastasis rates at different stations (pericolic, intermediate and apical LN) were compared between the two groups (Fig. 2). For the ICR group (n = 559), the metastasis rate of pericolic lymph nodes was the highest (38.3%), followed by intermediate lymph nodes (12.9%), apical lymph nodes (3.8%) (Fig. 2A). For the RHC group (n = 454), the metastasis rate of pericolic lymph nodes was also the highest (7.0-14.1%), followed by intermediate lymph nodes (2.4–8.4%), apical lymph nodes (0.7-4.0%), and paravertebral lymph nodes of the abdominal aorta (0.9%) (Fig. 2B). Subgroup analysis showed that in patients with ascending colon cancer (n = 305) and transverse colon cancer (n = 149) in the RHC group. For the 305 patients with distal ascending colon cancer in RHC group, the metastasis rate of pericolic lymph nodes was the highest (4.3–28.9%), followed by intermediate lymph nodes (2.3–10.2%), apical lymph nodes (0.7–2.3%), and paravertebral lymph nodes of the abdominal aorta (1.3%) (Fig. 2C). For the 149 patients with transverse colon cancer in RHC group, the metastasis rate of pericolic lymph nodes was 4.0-34.2%, followed by intermediate lymph nodes (0.7–16.1%), apical lymph nodes (0.7–7.4%), and no paravertebral lymph nodes of the abdominal aorta LN metastasis was observed (0%) (Fig. 2D). The median follow-up period was 96 months. Comparisons of 5-year OS, CSS, and RFS between the two groups before and after PSM are shown in Fig. 3. Before PSM, the 5-year OS was 69.2% in the RHC group and 63.9% in the ICR group (p = 0.341), the 5-year CSS was 75.6% in the RHC group and 70.8% in the ICR group (p = 0.487), and the 5-year RFS was 69.8% in the RHC group and 70.4% in the ICR group (p = 0.497). After PSM, the 5-year OS was 70.8% in the RHC group and 62.7% in the ICR group (p = 0.137), the 5-year CSS was 77.4% in the RHC group and 69.4% in the ICR group (p = 0.190), and the 5-year RFS was 72.2% in the RHC group and 71.4% in the ICR group (p = 0.526). No significant differences in 5-year OS, CSS, or RFS were observed between the two groups before or after PSM (all N.S.). Multivariate logistic regression analysis was performed to identify independent prognostic factors for OS, CSS, and RFS (Tables 3, 4, 5). For OS, independent prognostic factors included CEA level (HR = 2.3, 95%CI: 1.4–3.8, p < 0.001), histology type (poorly differentiated, signet ring, mucinous carcinoma vs. well, moderately differentiated adenocarcinoma; HR = 3.1, 95%CI: 1.9–5.2, p < 0.001), venous invasion (HR = 2.1, 95%CI: 1.0–4.4, p = 0.046), and pN stage (pN2-3 vs. pN1; HR = 2.7, 95%CI: 1.5–4.9, p = 0.001) (Tables 3). A high CEA level was a common independent risk factor for high risk in OS, CSS, and RFS (Tables 3, 4, 5). Notably, a high CEA level was a common independent high-risk factor for OS, CSS, and RFS. The surgical approach (ICR vs. RHC) was not an independent prognostic factor for OS, CSS, or RFS (all N.S.). The recurrence patterns were compared between the two groups before and after PSM (Table 6). Before PSM, the total metastasis rate was 21.8% in the RHC group and 23.3% in the ICR group (N.S). The most common recurrence site was the liver (6.5% in the RHC group vs. 11.7% in the ICR group, N.S), followed by the peritoneum (3.2% vs. 7.2%, N.S.), lung (6.0% vs. 4.0%, N.S.), and lymph nodes (5.1% vs. 2.2%, N.S.). After PSM, the total metastasis rate was 20.5% in the RHC group and 23.2% in the ICR group (N.S.), with no significant differences in the recurrence rate of each site between the two groups (all N.S.). No significant difference in perioperative complications was observed between the two groups (16.9% vs. 18.6%, N.S.). Discussion This retrospective study from Saitama Medical University International Medical Center compared lymph node distribution patterns, surgical outcomes, and long-term oncologic outcomes between RHC and ICR in 439 patients with stage III right-sided colon cancer (216 in the RHC group and 223 in the ICR group) treated between April 2007 and December 2020. After PSM, the results demonstrated that RHC achieved a higher number of excised lymph nodes compared with ICR; however, no significant differences were observed in 5-year OS, CSS, RFS, or recurrence patterns between the two groups. These findings suggest that ICR may be a feasible alternative to RHC for patients with stage III right-sided colon cancer whose tumors are located in the cecum or proximal ascending colon. Lymph node dissection is a critical component of surgical treatment for colon cancer, as the number of excised lymph nodes and the presence of lymph node metastasis are important prognostic factors. [ 9 ]. In this study, the mean number of excised lymph nodes was significantly higher in the RHC group than in the ICR group both before and after PSM (36.0 vs. 26.4 before PSM, 36.0 vs. 26.0 after PSM, both p < 0.001), In this study, the mean number of excised lymph nodes was significantly higher in the RHC group than in the ICR group both before and after PSM (36.0 vs. 26.4 before PSM, 36.0 vs. 26.0 after PSM, both p < 0.001), which is consistent with previous studies showing that RHC can achieve more extensive lymph node dissection than ICR[ 10 , 11 ]. The higher number of excised lymph nodes in the RHC group may be attributed to the more extensive resection of the mesentery and the inclusion of additional lymph node stations (including apical lymph nodes) during surgery. Nevertheless, the number of metastatic lymph nodes did not differ significantly between the two groups, indicating that the extent of lymph node metastasis may not be influenced by the surgical approach. The D1 nodal metastasis rate was significantly lower in the RHC group than in the ICR group both before and after PSM (86.1% vs. 96.0% before PSM, 87.0% vs. 95.7% after PSM, both p < 0.05). D1 lymph nodes are pericolic lymph nodes located near the tumor, and their metastasis rate is an indicator of the local invasiveness of the tumor[ 12 ]. The lower D1 nodal metastasis rate in the RHC group may be due to the larger resection margin and the more complete removal of the tumor and surrounding tissues, which reduces the risk of residual tumor cells in the local lymph nodes[ 13 , 14 ]. However, the clinical significance of this finding remains unclear, as it did not translate into better long-term survival outcomes. In terms of surgical outcomes, the ICR group had a shorter operative time and less operative blood loss than the RHC group before PSM, which is consistent with the minimally invasive nature of ICR [ 15 ]. After PSM, the operative time was still significantly shorter in the ICR group than in the RHC group (149 vs. 189 min, p < 0.001), indicating that ICR is associated with less surgical trauma and faster intraoperative recovery. No significant differences were observed in postoperative complications, postoperative hospital stay, or time to first food intake between the two groups, suggesting that both surgical approaches are safe and well-tolerated by patients. Long-term oncologic outcomes are the most important indicators for evaluating the effectiveness of surgical procedures. In this study, no significant differences in 5-year OS, CSS, or RFS were found between the RHC and ICR groups before or after PSM. This is consistent with some previous studies [ 10 , 16 ], but contradicts others[ 11 , 17 ]. The inconsistency between studies may be due to differences in patient selection, surgical techniques, and follow-up duration. For example, some studies included only patients with tumors located near the ileocecal valve, while others included patients with tumors throughout the ascending colon. In the present study, patients were carefully selected, and PSM was used to balance baseline characteristics, thereby reducing the impact of confounding factors on the results. Multivariate logistic regression analysis showed that histology type, venous invasion, and pN stage were independent prognostic factors for CSS, while pN stage was an independent prognostic factor for RFS. These findings are consistent with previous studies indicating that poor histology type, venous invasion, and advanced pN stage are associated with a worse prognosis in patients with colon cancer. [ 16 , 18 ] The surgical approach (ICR vs. RHC) was not an independent prognostic factor, suggesting that the choice of surgical procedure does not affect the long-term prognosis of patients with stage III right-sided colon cancer. Recurrence patterns were similar between the two groups, with the liver being the most common recurrence site, followed by the peritoneum, lung, and lymph nodes. This is consistent with the typical recurrence patterns of right-sided colon cancer [ 19 ]. No significant differences in the recurrence rate of each site were observed between the two groups, indicating that the surgical approach does not influence the pattern of tumor recurrence [ 6 , 10 ]. This study has several limitations. First, it is a retrospective single-center study, which may be subject to selection bias and information bias. Second, the follow-up duration was 5 years, and longer follow-up is needed to evaluate the long-term oncologic outcomes of the two surgical approaches. Third, the study did not assess the quality of life of patients after surgery, which is an important indicator for evaluating the effectiveness of surgical procedures. Fourth, the study did not stratify patients according to tumor location (e.g., cecum vs. ascending colon), which may affect the results, as the optimal surgical approach may vary depending on tumor location. Further prospective multicenter studies with longer follow-up are required to confirm these findings. Conclusion In conclusion, for patients with stage III right-sided colon cancer, RHC achieves a higher number of excised lymph nodes compared with ICR. However, the number of metastatic lymph nodes does not differ significantly between the two groups, and there are no significant differences in long-term oncologic outcomes. Given the advantages of shorter operative time and less surgical trauma associated with ICR, it can serve as a reasonable alternative to RHC for patients with stage III right-sided colon cancer whose tumors are located in the cecum or proximal ascending colon. Declarations Conflicts of interest The authors declare no competing interests related to this study. Funding No funding was received for this study. Author Contribution Liming Wang and Bolun Song drafted the manuscript and prepared the original figures. Yasumitsu Hirano reviewed and revised the manuscript. All authors approved the final version for submission. Data availability The data used and/or analyzed during the current study are available from the corresponding author on reasonable request. References Siegel RL, Miller KD, Wagle NS et al (2023) Cancer statistics, 2023. CA Cancer J Clin 73:17–48. 10.3322/caac.21763 Benson AB, Venook AP, Al-Hawary MM et al (2021) Colon Cancer, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw 19:329–359. 10.6004/jnccn.2021.0012 Saha S, Wiese D, Badin J et al (2000) Technical details of sentinel lymph node mapping in colorectal cancer and its impact on staging. Ann Surg Oncol 7:120–124. 10.1007/s10434-000-0120-z Jung HS, Ryoo SB, Lim HK et al (2021) Tumor Size > 5 cm and Harvested LNs < 12 Are the Risk Factors for Recurrence in Stage I Colon and Rectal Cancer after Radical Resection. Cancers (Basel) 13. 10.3390/cancers13215294 Japanese Society for Cancer of the C, Rectum (2019) Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma: the 3d English Edition [Secondary Publication]. J Anus Rectum Colon 3:175–195. 10.23922/jarc.2019-018 Hashiguchi Y, Muro K, Saito Y et al (2020) Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2019 for the treatment of colorectal cancer. Int J Clin Oncol 25:1–42. 10.1007/s10147-019-01485-z Kwak HD, Ju JK, Lee SY et al (2019) The relation between oncologic outcomes and metastatic lymph node location following laparoscopic resection of stage III colon cancer. Int J Colorectal Dis 34:667–673. 10.1007/s00384-019-03245-x Ankersmit M, Bonjer HJ, Hannink G et al (2019) Near-infrared fluorescence imaging for sentinel lymph node identification in colon cancer: a prospective single-center study and systematic review with meta-analysis. Tech Coloproctol 23:1113–1126. 10.1007/s10151-019-02107-6 van der Pas MH, Meijer S, Hoekstra OS et al (2011) Sentinel-lymph-node procedure in colon and rectal cancer: a systematic review and meta-analysis. Lancet Oncol 12:540–550. 10.1016/S1470-2045(11)70075-4 Tsukamoto S, Ouchi A, Komori K et al (2023) A multicenter prospective observational study of lymph node metastasis patterns and short-term outcomes of extended lymphadenectomy in right-sided colon cancer. Ann Gastroenterol Surg 7:940–948. 10.1002/ags3.12703 Lucas K, Melling N, Giannou AD et al (2023) Lymphatic Mapping in Colon Cancer Depending on Injection Time and Tracing Agent: A Systematic Review and Meta-Analysis of Prospective Designed Studies. Cancers (Basel) 15. 10.3390/cancers15123196 Wang LM, Hirano YM, Ishii TM et al (2020) The role of apical lymph node metastasis in right colon cancer. Int J Colorectal Dis 35:1887–1894. 10.1007/s00384-020-03661-4 West NP, Kobayashi H, Takahashi K et al (2012) Understanding optimal colonic cancer surgery: comparison of Japanese D3 resection and European complete mesocolic excision with central vascular ligation. J Clin Oncol 30:1763–1769. 10.1200/JCO.2011.38.3992 Soares AS, Lovat LB, Chand M (2019) Intracorporeal lymph node mapping in colon cancer surgery. Eur J Surg Oncol 45:2316–2318. 10.1016/j.ejso.2019.07.013 Son GM, Yun MS, Lee IY et al (2023) Clinical Effectiveness of Fluorescence Lymph Node Mapping Using ICG for Laparoscopic Right Hemicolectomy: A Prospective Case-Control Study. Cancers (Basel) 15. 10.3390/cancers15204927 Kataoka K, Beppu N, Shiozawa M et al (2020) Colorectal cancer treated by resection and extended lymphadenectomy: patterns of spread in left- and right-sided tumours. Br J Surg 107:1070–1078. 10.1002/bjs.11517 Saha S, Sehgal R, Patel M et al (2006) A multicenter trial of sentinel lymph node mapping in colorectal cancer: prognostic implications for nodal staging and recurrence. Am J Surg 191:305–310. 10.1016/j.amjsurg.2005.10.028 Son GM, Kim TU, Yun MS et al (2024) Effect of Fluorescence Lymph Node Mapping on Improving Diagnostic Values of CT D3 Lymph Node Staging for Right-Sided Colon Cancer. Cancers (Basel) 16. 10.3390/cancers16203496 Xu L, Su X, He Z et al (2021) Short-term outcomes of complete mesocolic excision versus D2 dissection in patients undergoing laparoscopic colectomy for right colon cancer (RELARC): a randomised, controlled, phase 3, superiority trial. Lancet Oncol 22:391–401. 10.1016/S1470-2045(20)30685-9 Tables Table 1 to 6 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Slide4.png Table 1 Slide5.png Table 2 Slide6.png Table 3 4 5 Slide7.png Table 6 Cite Share Download PDF Status: Posted Version 1 posted 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8757786","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":589376380,"identity":"faedb443-1190-4a73-8edd-ded97551c659","order_by":0,"name":"Bolun Song","email":"","orcid":"","institution":"National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital \u0026 Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China","correspondingAuthor":false,"prefix":"","firstName":"Bolun","middleName":"","lastName":"Song","suffix":""},{"id":589376381,"identity":"e9e5b6b6-e079-49e4-94d5-ef836ffcad84","order_by":1,"name":"Liming Wang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyElEQVRIiWNgGAWjYJCCA0DMwy8BZkvIEK9FcgYDYwNQCw/xVhncAGthIKzF4EZ24uGCmm0yxrebjz+6UWPBw8B++OgG/FpyNxyecew2j9mdY4nNOceADuNJS7uBT4sZSAsPG1DLjRzD5hw2oBYJIJuwln+3eYxngLT8I1YLb9ttHgMJoJbcNiK02J95C9TSd5tH4kZa4uzcPgkeNkJ+kWzP3fyZ59tte/4ZyQc+53yrk+NnP3wMrxZMwEaa8lEwCkbBKBgF2AAAT6FKz7DqJjUAAAAASUVORK5CYII=","orcid":"","institution":"National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital \u0026 Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China","correspondingAuthor":true,"prefix":"","firstName":"Liming","middleName":"","lastName":"Wang","suffix":""},{"id":589376382,"identity":"5d35dadf-a95a-4396-b3b2-6ba28b8c903e","order_by":2,"name":"Yinggang Chen","email":"","orcid":"","institution":"National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital \u0026 Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China","correspondingAuthor":false,"prefix":"","firstName":"Yinggang","middleName":"","lastName":"Chen","suffix":""},{"id":589376383,"identity":"39be6158-d684-40f8-aaee-b0fc32c2c540","order_by":3,"name":"Yasumitsu Hirano²","email":"","orcid":"","institution":"Division of Gastroenterological Surgery, Saitama Medical University International Medical Center, Saitama, Japan","correspondingAuthor":false,"prefix":"","firstName":"Yasumitsu","middleName":"","lastName":"Hirano²","suffix":""}],"badges":[],"createdAt":"2026-02-01 16:53:03","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8757786/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8757786/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102553308,"identity":"0e7ab034-e17e-463c-b746-8d35b24977f2","added_by":"auto","created_at":"2026-02-13 01:12:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":37790,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"Slide1.png","url":"https://assets-eu.researchsquare.com/files/rs-8757786/v1/0918c9e3c216cf40862296f4.png"},{"id":102553312,"identity":"316ae76b-342b-46e4-b929-60c74424f210","added_by":"auto","created_at":"2026-02-13 01:12:32","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":120817,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"Slide2.png","url":"https://assets-eu.researchsquare.com/files/rs-8757786/v1/c2d48c36dd9e34295c65c4db.png"},{"id":102553310,"identity":"538acff4-4ce6-4cf5-892e-8b66485ec076","added_by":"auto","created_at":"2026-02-13 01:12:32","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":80466,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"Slide3.png","url":"https://assets-eu.researchsquare.com/files/rs-8757786/v1/a0c8e197d62d89757e27d776.png"},{"id":105563963,"identity":"a3998356-9f21-4374-92d0-ef3dbd601f1f","added_by":"auto","created_at":"2026-03-27 12:48:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":612529,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8757786/v1/63e28d5d-644b-471e-948d-28f006197e85.pdf"},{"id":102553311,"identity":"8207f3e7-10f7-4bb4-ba7c-2c3355b6e53d","added_by":"auto","created_at":"2026-02-13 01:12:32","extension":"png","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":32012,"visible":true,"origin":"","legend":"\u003cp\u003eTable 1\u003c/p\u003e","description":"","filename":"Slide4.png","url":"https://assets-eu.researchsquare.com/files/rs-8757786/v1/15346a0b3a221d83ce509315.png"},{"id":102553306,"identity":"a1ae0595-c044-40e8-a701-513af0803667","added_by":"auto","created_at":"2026-02-13 01:12:31","extension":"png","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":35159,"visible":true,"origin":"","legend":"\u003cp\u003eTable 2\u003c/p\u003e","description":"","filename":"Slide5.png","url":"https://assets-eu.researchsquare.com/files/rs-8757786/v1/33f319eecd390b1160ac4fa6.png"},{"id":102553307,"identity":"9b1bf403-d129-45fe-8b29-d84c7d39977a","added_by":"auto","created_at":"2026-02-13 01:12:32","extension":"png","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":39754,"visible":true,"origin":"","legend":"\u003cp\u003eTable 3 4 5\u003c/p\u003e","description":"","filename":"Slide6.png","url":"https://assets-eu.researchsquare.com/files/rs-8757786/v1/fff5fe26bbb5f09d57430468.png"},{"id":102746581,"identity":"10ed4eb1-f68a-42c2-b9fd-20d1bb8faa28","added_by":"auto","created_at":"2026-02-16 08:58:22","extension":"png","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":32462,"visible":true,"origin":"","legend":"\u003cp\u003eTable 6\u003c/p\u003e","description":"","filename":"Slide7.png","url":"https://assets-eu.researchsquare.com/files/rs-8757786/v1/d53a8cbd184092763b3987ca.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Lymph Node Distribution Patterns and Oncologic Outcomes: A Propensity Score-Matched Retrospective Comparison of Right Hemicolectomy versus Ileocecal Resection in Stage III Right-Sided Colon Cancer","fulltext":[{"header":"Introduction","content":"\u003cp\u003eColorectal cancer (CRC) is one of the most common malignant tumors worldwide, with right-sided colon cancer accounting for approximately 30%\u0026ndash;40% of all CRC cases [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Lymph node metastasis is a key prognostic factor for patients with CRC, and complete lymph node dissection is crucial for accurate staging and improving long-term survival [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. For right-sided colon cancer, the standard surgical procedure is right hemicolectomy (RHC), which involves resection of the ascending colon, cecum, terminal ileum, and associated mesentery, along with complete lymph node dissection[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. However, ileocecal resection (ICR), which resects the cecum, ileocecal valve, and a short segment of the terminal ileum and ascending colon, is also widely used in clinical practice, especially for tumors located near the ileocecal valve [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe controversy surrounding RHC and ICR mainly focuses on whether ICR can achieve equivalent lymph node dissection completeness and oncologic outcomes compared with RHC, especially in stage III right-sided colon cancer. Some studies have shown that ICR is associated with fewer excised lymph nodes and a higher risk of incomplete lymph node dissection, which may compromise staging accuracy and long-term survival[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. In contrast, other studies have suggested that ICR can achieve similar oncologic outcomes to RHC for selected patients with right-sided colon cancer, with the advantages of less surgical trauma, shorter operative time, and faster postoperative recovery [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo clarify the differences in lymph node distribution patterns, surgical outcomes, and long-term survival between RHC and ICR in patients with stage III right-sided colon cancer. This study aimed to provide clinical evidence for the rational choice of surgical procedure for stage III right-sided colon cancer.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eA retrospective study was conducted at the Division of Gastroenterological Surgery, Saitama Medical University International Medical Center, covering a 13-year period from April 2007 to December 2020. The median follow-up duration was 96 months. The study was approved by the Ethics Committee of the International Medical Center of Saitama Medical University (Ethics Review No. : IRB2023-036), and written informed consent was obtained from all participants.\u003c/p\u003e \u003cp\u003e The inclusion criteria were: (1) pathologically confirmed primary right-sided colon cancer (located in the cecum, ascending colon, or hepatic flexure); (2) stage III disease according to the American Joint Committee on Cancer (AJCC) TNM staging system (8th edition); (3) underwent RHC or ICR; (4) complete clinical, surgical, and follow-up data. The exclusion criteria were: (1) multiple malignant tumors; (2) recurrent colon cancer; (3) distant metastasis at diagnosis; (4) underwent total colectomy; (5) no lymph node metastasis; (6) incomplete clinical or follow-up data.\u003c/p\u003e \u003cp\u003eAll surgical procedures were performed by experienced surgeons in the Division of Gastroenterological Surgery, in accordance with the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma (JCCRC)[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. RHC was performed for tumors in the distal ascending colon or hepatic flexure with resection of the terminal ileum (5\u0026ndash;10 cm), cecum, ascending colon, hepatic flexure. The procedure involved the resection of the terminal ileum (5\u0026ndash;10 cm), cecum, ascending colon, hepatic flexure, and a portion of the transverse colon, along with complete mesocolic excision and central vascular ligation to ensure adequate lymph node dissection (including pericolic, intermediate, and apical lymph nodes). ICR was performed for tumors in the cecum or proximal ascending colon when no blood supply from the right branch of the middle colic artery extended beyond 10 cm distal to the tumor. The procedure involved the resection of the terminal ileum (10 cm), cecum, ileocecal valve, and a 10 cm segment of the ascending colon distal to the tumor, along with lymph node dissection around the ileocolic vessels (including pericolic, intermediate, and apical lymph nodes).\u003c/p\u003e \u003cp\u003eClinical data were collected from the hospital\u0026rsquo;s electronic medical records, including baseline characteristics (gender, age, body mass index [BMI], carcinoembryonic antigen [CEA] level, tumor family history, abdominal surgery history, comorbidities), surgical parameters (operative method, operative time, operative blood loss, postoperative complications, postoperative hospital stay, time to first food intake, adjuvant chemotherapy), pathological characteristics (tumor size, resection margins, gross type, histology type, infiltration form, lymphatic invasion, venous invasion, number of excised lymph nodes, number of metastatic lymph nodes, pT stage, pN stage, lymph node metastasis at different stations), and follow-up data (survival status, recurrence status, recurrence site).\u003c/p\u003e \u003cp\u003eAll patients were followed up regularly after surgery. The follow-up schedule was every 3 months for the first 3 years, every 6 months for years 4\u0026ndash;5, and annually thereafter. Follow-up examinations included physical examination, blood tests (CEA, CA19-9), abdominal computed tomography (CT), chest CT, and colonoscopy every year. The primary endpoints were 5-year overall survival (OS), 5-year cancer-specific survival (CSS), and 5-year relapse-free survival (RFS). OS was defined as the time from surgery to death from any cause. CSS was defined as the time from surgery to death from colon cancer. RFS was defined as the time from surgery to the first occurrence of local recurrence or distant metastasis.\u003c/p\u003e \u003cp\u003eStatistical analysis was performed using SPSS 22.0 software (IBM Corp., Tokyo, Japan). Continuous variables were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) and compared using the t-test or Mann-Whitney U test. Categorical variables were expressed as counts and percentages and compared using the χ\u0026sup2; test or Fisher\u0026rsquo;s exact test. Propensity score matching (PSM) was used to balance baseline characteristics between the RHC and ICR groups at a 1:1 ratio, with a caliper width of 0.2. The variables included in PSM were gender, age, BMI, CEA level, tumor family history, abdominal surgery history, comorbidity, operative method, and pT stage. Survival curves were plotted using the Kaplan-Meier method and compared using the log-rank test. Multivariate logistic regression analysis was used to identify independent prognostic factors for OS, CSS, and RFS. A p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eDuring the study period, a total of 6273 patients with primary colorectal cancer were identified. Among them, 1013 patients had primary right-sided colon cancer, and 146 patients were excluded based on the exclusion criteria (multiple malignant tumors, recurrent cancer, distant metastasis, total colectomy). After excluding patients without lymph node metastasis, 216 patients in the RHC group and 223 patients in the ICR group were enrolled (Fig.\u0026nbsp;1). After PSM, 185 patients were included in each group, and no significant differences were observed in baseline characteristics between the two groups (all N.S.), indicating that the two groups were well balanced (Table\u0026nbsp;1).\u003c/p\u003e \u003cp\u003eBefore PSM, the proportion of laparoscopic surgery was significantly higher in the ICR group than in the RHC group (90.1% vs. 78.7%, p\u0026thinsp;=\u0026thinsp;0.001), the operative time was significantly shorter in the ICR group (152\u0026thinsp;\u0026plusmn;\u0026thinsp;58.2 min vs. 193\u0026thinsp;\u0026plusmn;\u0026thinsp;66.4 min, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and the operative blood loss was significantly less in the ICR group (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There were no significant differences in postoperative complications, postoperative hospital stays, time to first food intake, or adjuvant chemotherapy rate between the two groups (all N.S). After PSM, there were no significant differences in laparoscopic surgery rate, operative blood loss, postoperative complications, postoperative hospital stay, time to first food intake, or adjuvant chemotherapy rate between the two groups (all N.S), but the operative time was still significantly shorter in the ICR group than in the RHC group (149\u0026thinsp;\u0026plusmn;\u0026thinsp;60.0 min vs. 189\u0026thinsp;\u0026plusmn;\u0026thinsp;61.1 min, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table\u0026nbsp;1).\u003c/p\u003e \u003cp\u003eBefore PSM, the mean tumor size was significantly larger in the RHC group than in the ICR group (5.39\u0026thinsp;\u0026plusmn;\u0026thinsp;2.59 cm vs. 4.90\u0026thinsp;\u0026plusmn;\u0026thinsp;2.28 cm, p\u0026thinsp;=\u0026thinsp;0.037), the mean proximal resection margin was significantly longer in the RHC group (14.5\u0026thinsp;\u0026plusmn;\u0026thinsp;6.52 cm vs. 11.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.88 cm, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), the mean number of excised lymph nodes was significantly higher in the RHC group (36.0\u0026thinsp;\u0026plusmn;\u0026thinsp;15.0 vs. 26.4\u0026thinsp;\u0026plusmn;\u0026thinsp;10.6, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), the pT stage distribution was significantly different between the two groups (p\u0026thinsp;=\u0026thinsp;0.019), and the pN stage distribution was significantly different between the two groups (p\u0026thinsp;=\u0026thinsp;0.026). The D1 nodal metastasis rate was significantly lower in the RHC group than in the ICR group (86.1% vs. 96.0%, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There were no significant differences in distal resection margin, gross type, histology type, infiltration form, lymphatic invasion, venous invasion, or number of metastatic lymph nodes between the two groups (all N.S).\u003c/p\u003e \u003cp\u003eAfter PSM, there were no significant differences in tumor size, pT stage, pN stage, or other pathological characteristics between the two groups (all N.S), except that the mean proximal resection margin was still significantly longer in the RHC group than in the ICR group (14.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.48 cm vs. 12.0\u0026thinsp;\u0026plusmn;\u0026thinsp;6.16 cm, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and the mean number of excised lymph nodes was still significantly higher in the RHC group than in the ICR group (36.0\u0026thinsp;\u0026plusmn;\u0026thinsp;13.8 vs. 26.0\u0026thinsp;\u0026plusmn;\u0026thinsp;10.7, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The D1 nodal metastasis rate was still significantly lower in the RHC group than in the ICR group (87.0% vs.95.7%, p\u0026thinsp;=\u0026thinsp;0.005) (Table\u0026nbsp;2).\u003c/p\u003e \u003cp\u003eThe lymph node metastasis rates at different stations (pericolic, intermediate and apical LN) were compared between the two groups (Fig.\u0026nbsp;2). For the ICR group (n\u0026thinsp;=\u0026thinsp;559), the metastasis rate of pericolic lymph nodes was the highest (38.3%), followed by intermediate lymph nodes (12.9%), apical lymph nodes (3.8%) (Fig.\u0026nbsp;2A). For the RHC group (n\u0026thinsp;=\u0026thinsp;454), the metastasis rate of pericolic lymph nodes was also the highest (7.0-14.1%), followed by intermediate lymph nodes (2.4\u0026ndash;8.4%), apical lymph nodes (0.7-4.0%), and paravertebral lymph nodes of the abdominal aorta (0.9%) (Fig.\u0026nbsp;2B). Subgroup analysis showed that in patients with ascending colon cancer (n\u0026thinsp;=\u0026thinsp;305) and transverse colon cancer (n\u0026thinsp;=\u0026thinsp;149) in the RHC group. For the 305 patients with distal ascending colon cancer in RHC group, the metastasis rate of pericolic lymph nodes was the highest (4.3\u0026ndash;28.9%), followed by intermediate lymph nodes (2.3\u0026ndash;10.2%), apical lymph nodes (0.7\u0026ndash;2.3%), and paravertebral lymph nodes of the abdominal aorta (1.3%) (Fig.\u0026nbsp;2C). For the 149 patients with transverse colon cancer in RHC group, the metastasis rate of pericolic lymph nodes was 4.0-34.2%, followed by intermediate lymph nodes (0.7\u0026ndash;16.1%), apical lymph nodes (0.7\u0026ndash;7.4%), and no paravertebral lymph nodes of the abdominal aorta LN metastasis was observed (0%) (Fig.\u0026nbsp;2D).\u003c/p\u003e \u003cp\u003eThe median follow-up period was 96 months. Comparisons of 5-year OS, CSS, and RFS between the two groups before and after PSM are shown in Fig.\u0026nbsp;3. Before PSM, the 5-year OS was 69.2% in the RHC group and 63.9% in the ICR group (p\u0026thinsp;=\u0026thinsp;0.341), the 5-year CSS was 75.6% in the RHC group and 70.8% in the ICR group (p\u0026thinsp;=\u0026thinsp;0.487), and the 5-year RFS was 69.8% in the RHC group and 70.4% in the ICR group (p\u0026thinsp;=\u0026thinsp;0.497). After PSM, the 5-year OS was 70.8% in the RHC group and 62.7% in the ICR group (p\u0026thinsp;=\u0026thinsp;0.137), the 5-year CSS was 77.4% in the RHC group and 69.4% in the ICR group (p\u0026thinsp;=\u0026thinsp;0.190), and the 5-year RFS was 72.2% in the RHC group and 71.4% in the ICR group (p\u0026thinsp;=\u0026thinsp;0.526). No significant differences in 5-year OS, CSS, or RFS were observed between the two groups before or after PSM (all N.S.).\u003c/p\u003e \u003cp\u003eMultivariate logistic regression analysis was performed to identify independent prognostic factors for OS, CSS, and RFS (Tables\u0026nbsp;3, 4, 5). For OS, independent prognostic factors included CEA level (HR\u0026thinsp;=\u0026thinsp;2.3, 95%CI: 1.4\u0026ndash;3.8, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), histology type (poorly differentiated, signet ring, mucinous carcinoma vs. well, moderately differentiated adenocarcinoma; HR\u0026thinsp;=\u0026thinsp;3.1, 95%CI: 1.9\u0026ndash;5.2, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), venous invasion (HR\u0026thinsp;=\u0026thinsp;2.1, 95%CI: 1.0\u0026ndash;4.4, p\u0026thinsp;=\u0026thinsp;0.046), and pN stage (pN2-3 vs. pN1; HR\u0026thinsp;=\u0026thinsp;2.7, 95%CI: 1.5\u0026ndash;4.9, p\u0026thinsp;=\u0026thinsp;0.001) (Tables\u0026nbsp;3). A high CEA level was a common independent risk factor for high risk in OS, CSS, and RFS (Tables\u0026nbsp;3, 4, 5). Notably, a high CEA level was a common independent high-risk factor for OS, CSS, and RFS. The surgical approach (ICR vs. RHC) was not an independent prognostic factor for OS, CSS, or RFS (all N.S.).\u003c/p\u003e \u003cp\u003eThe recurrence patterns were compared between the two groups before and after PSM (Table\u0026nbsp;6). Before PSM, the total metastasis rate was 21.8% in the RHC group and 23.3% in the ICR group (N.S). The most common recurrence site was the liver (6.5% in the RHC group vs. 11.7% in the ICR group, N.S), followed by the peritoneum (3.2% vs. 7.2%, N.S.), lung (6.0% vs. 4.0%, N.S.), and lymph nodes (5.1% vs. 2.2%, N.S.). After PSM, the total metastasis rate was 20.5% in the RHC group and 23.2% in the ICR group (N.S.), with no significant differences in the recurrence rate of each site between the two groups (all N.S.). No significant difference in perioperative complications was observed between the two groups (16.9% vs. 18.6%, N.S.).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis retrospective study from Saitama Medical University International Medical Center compared lymph node distribution patterns, surgical outcomes, and long-term oncologic outcomes between RHC and ICR in 439 patients with stage III right-sided colon cancer (216 in the RHC group and 223 in the ICR group) treated between April 2007 and December 2020. After PSM, the results demonstrated that RHC achieved a higher number of excised lymph nodes compared with ICR; however, no significant differences were observed in 5-year OS, CSS, RFS, or recurrence patterns between the two groups. These findings suggest that ICR may be a feasible alternative to RHC for patients with stage III right-sided colon cancer whose tumors are located in the cecum or proximal ascending colon.\u003c/p\u003e \u003cp\u003eLymph node dissection is a critical component of surgical treatment for colon cancer, as the number of excised lymph nodes and the presence of lymph node metastasis are important prognostic factors. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In this study, the mean number of excised lymph nodes was significantly higher in the RHC group than in the ICR group both before and after PSM (36.0 vs. 26.4 before PSM, 36.0 vs. 26.0 after PSM, both p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), In this study, the mean number of excised lymph nodes was significantly higher in the RHC group than in the ICR group both before and after PSM (36.0 vs. 26.4 before PSM, 36.0 vs. 26.0 after PSM, both p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), which is consistent with previous studies showing that RHC can achieve more extensive lymph node dissection than ICR[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The higher number of excised lymph nodes in the RHC group may be attributed to the more extensive resection of the mesentery and the inclusion of additional lymph node stations (including apical lymph nodes) during surgery. Nevertheless, the number of metastatic lymph nodes did not differ significantly between the two groups, indicating that the extent of lymph node metastasis may not be influenced by the surgical approach.\u003c/p\u003e \u003cp\u003eThe D1 nodal metastasis rate was significantly lower in the RHC group than in the ICR group both before and after PSM (86.1% vs. 96.0% before PSM, 87.0% vs. 95.7% after PSM, both p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). D1 lymph nodes are pericolic lymph nodes located near the tumor, and their metastasis rate is an indicator of the local invasiveness of the tumor[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The lower D1 nodal metastasis rate in the RHC group may be due to the larger resection margin and the more complete removal of the tumor and surrounding tissues, which reduces the risk of residual tumor cells in the local lymph nodes[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. However, the clinical significance of this finding remains unclear, as it did not translate into better long-term survival outcomes.\u003c/p\u003e \u003cp\u003eIn terms of surgical outcomes, the ICR group had a shorter operative time and less operative blood loss than the RHC group before PSM, which is consistent with the minimally invasive nature of ICR [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. After PSM, the operative time was still significantly shorter in the ICR group than in the RHC group (149 vs. 189 min, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating that ICR is associated with less surgical trauma and faster intraoperative recovery. No significant differences were observed in postoperative complications, postoperative hospital stay, or time to first food intake between the two groups, suggesting that both surgical approaches are safe and well-tolerated by patients.\u003c/p\u003e \u003cp\u003eLong-term oncologic outcomes are the most important indicators for evaluating the effectiveness of surgical procedures. In this study, no significant differences in 5-year OS, CSS, or RFS were found between the RHC and ICR groups before or after PSM. This is consistent with some previous studies [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], but contradicts others[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The inconsistency between studies may be due to differences in patient selection, surgical techniques, and follow-up duration. For example, some studies included only patients with tumors located near the ileocecal valve, while others included patients with tumors throughout the ascending colon. In the present study, patients were carefully selected, and PSM was used to balance baseline characteristics, thereby reducing the impact of confounding factors on the results.\u003c/p\u003e \u003cp\u003eMultivariate logistic regression analysis showed that histology type, venous invasion, and pN stage were independent prognostic factors for CSS, while pN stage was an independent prognostic factor for RFS. These findings are consistent with previous studies indicating that poor histology type, venous invasion, and advanced pN stage are associated with a worse prognosis in patients with colon cancer. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] The surgical approach (ICR vs. RHC) was not an independent prognostic factor, suggesting that the choice of surgical procedure does not affect the long-term prognosis of patients with stage III right-sided colon cancer.\u003c/p\u003e \u003cp\u003eRecurrence patterns were similar between the two groups, with the liver being the most common recurrence site, followed by the peritoneum, lung, and lymph nodes. This is consistent with the typical recurrence patterns of right-sided colon cancer [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. No significant differences in the recurrence rate of each site were observed between the two groups, indicating that the surgical approach does not influence the pattern of tumor recurrence [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThis study has several limitations. First, it is a retrospective single-center study, which may be subject to selection bias and information bias. Second, the follow-up duration was 5 years, and longer follow-up is needed to evaluate the long-term oncologic outcomes of the two surgical approaches. Third, the study did not assess the quality of life of patients after surgery, which is an important indicator for evaluating the effectiveness of surgical procedures. Fourth, the study did not stratify patients according to tumor location (e.g., cecum vs. ascending colon), which may affect the results, as the optimal surgical approach may vary depending on tumor location. Further prospective multicenter studies with longer follow-up are required to confirm these findings.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, for patients with stage III right-sided colon cancer, RHC achieves a higher number of excised lymph nodes compared with ICR. However, the number of metastatic lymph nodes does not differ significantly between the two groups, and there are no significant differences in long-term oncologic outcomes. Given the advantages of shorter operative time and less surgical trauma associated with ICR, it can serve as a reasonable alternative to RHC for patients with stage III right-sided colon cancer whose tumors are located in the cecum or proximal ascending colon.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflicts of interest\u003c/h2\u003e \u003cp\u003eThe authors declare no competing interests related to this study.\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eNo funding was received for this study.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eLiming Wang and Bolun Song drafted the manuscript and prepared the original figures. Yasumitsu Hirano reviewed and revised the manuscript. All authors approved the final version for submission.\u003c/p\u003e\u003ch2\u003eData availability\u003c/h2\u003e \u003cp\u003eThe data used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSiegel RL, Miller KD, Wagle NS et al (2023) Cancer statistics, 2023. CA Cancer J Clin 73:17\u0026ndash;48. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3322/caac.21763\u003c/span\u003e\u003cspan address=\"10.3322/caac.21763\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBenson AB, Venook AP, Al-Hawary MM et al (2021) Colon Cancer, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw 19:329\u0026ndash;359. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.6004/jnccn.2021.0012\u003c/span\u003e\u003cspan address=\"10.6004/jnccn.2021.0012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSaha S, Wiese D, Badin J et al (2000) Technical details of sentinel lymph node mapping in colorectal cancer and its impact on staging. Ann Surg Oncol 7:120\u0026ndash;124. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s10434-000-0120-z\u003c/span\u003e\u003cspan address=\"10.1007/s10434-000-0120-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJung HS, Ryoo SB, Lim HK et al (2021) Tumor Size\u0026thinsp;\u0026gt;\u0026thinsp;5 cm and Harvested LNs\u0026thinsp;\u0026lt;\u0026thinsp;12 Are the Risk Factors for Recurrence in Stage I Colon and Rectal Cancer after Radical Resection. Cancers (Basel) 13. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/cancers13215294\u003c/span\u003e\u003cspan address=\"10.3390/cancers13215294\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJapanese Society for Cancer of the C, Rectum (2019) Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma: the 3d English Edition [Secondary Publication]. J Anus Rectum Colon 3:175\u0026ndash;195. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.23922/jarc.2019-018\u003c/span\u003e\u003cspan address=\"10.23922/jarc.2019-018\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHashiguchi Y, Muro K, Saito Y et al (2020) Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2019 for the treatment of colorectal cancer. Int J Clin Oncol 25:1\u0026ndash;42. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s10147-019-01485-z\u003c/span\u003e\u003cspan address=\"10.1007/s10147-019-01485-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKwak HD, Ju JK, Lee SY et al (2019) The relation between oncologic outcomes and metastatic lymph node location following laparoscopic resection of stage III colon cancer. Int J Colorectal Dis 34:667\u0026ndash;673. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00384-019-03245-x\u003c/span\u003e\u003cspan address=\"10.1007/s00384-019-03245-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAnkersmit M, Bonjer HJ, Hannink G et al (2019) Near-infrared fluorescence imaging for sentinel lymph node identification in colon cancer: a prospective single-center study and systematic review with meta-analysis. Tech Coloproctol 23:1113\u0026ndash;1126. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s10151-019-02107-6\u003c/span\u003e\u003cspan address=\"10.1007/s10151-019-02107-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003evan der Pas MH, Meijer S, Hoekstra OS et al (2011) Sentinel-lymph-node procedure in colon and rectal cancer: a systematic review and meta-analysis. Lancet Oncol 12:540\u0026ndash;550. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1470-2045(11)70075-4\u003c/span\u003e\u003cspan address=\"10.1016/S1470-2045(11)70075-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTsukamoto S, Ouchi A, Komori K et al (2023) A multicenter prospective observational study of lymph node metastasis patterns and short-term outcomes of extended lymphadenectomy in right-sided colon cancer. Ann Gastroenterol Surg 7:940\u0026ndash;948. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/ags3.12703\u003c/span\u003e\u003cspan address=\"10.1002/ags3.12703\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLucas K, Melling N, Giannou AD et al (2023) Lymphatic Mapping in Colon Cancer Depending on Injection Time and Tracing Agent: A Systematic Review and Meta-Analysis of Prospective Designed Studies. Cancers (Basel) 15. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/cancers15123196\u003c/span\u003e\u003cspan address=\"10.3390/cancers15123196\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang LM, Hirano YM, Ishii TM et al (2020) The role of apical lymph node metastasis in right colon cancer. Int J Colorectal Dis 35:1887\u0026ndash;1894. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00384-020-03661-4\u003c/span\u003e\u003cspan address=\"10.1007/s00384-020-03661-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWest NP, Kobayashi H, Takahashi K et al (2012) Understanding optimal colonic cancer surgery: comparison of Japanese D3 resection and European complete mesocolic excision with central vascular ligation. J Clin Oncol 30:1763\u0026ndash;1769. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1200/JCO.2011.38.3992\u003c/span\u003e\u003cspan address=\"10.1200/JCO.2011.38.3992\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSoares AS, Lovat LB, Chand M (2019) Intracorporeal lymph node mapping in colon cancer surgery. Eur J Surg Oncol 45:2316\u0026ndash;2318. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ejso.2019.07.013\u003c/span\u003e\u003cspan address=\"10.1016/j.ejso.2019.07.013\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSon GM, Yun MS, Lee IY et al (2023) Clinical Effectiveness of Fluorescence Lymph Node Mapping Using ICG for Laparoscopic Right Hemicolectomy: A Prospective Case-Control Study. Cancers (Basel) 15. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/cancers15204927\u003c/span\u003e\u003cspan address=\"10.3390/cancers15204927\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKataoka K, Beppu N, Shiozawa M et al (2020) Colorectal cancer treated by resection and extended lymphadenectomy: patterns of spread in left- and right-sided tumours. Br J Surg 107:1070\u0026ndash;1078. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/bjs.11517\u003c/span\u003e\u003cspan address=\"10.1002/bjs.11517\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSaha S, Sehgal R, Patel M et al (2006) A multicenter trial of sentinel lymph node mapping in colorectal cancer: prognostic implications for nodal staging and recurrence. Am J Surg 191:305\u0026ndash;310. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.amjsurg.2005.10.028\u003c/span\u003e\u003cspan address=\"10.1016/j.amjsurg.2005.10.028\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSon GM, Kim TU, Yun MS et al (2024) Effect of Fluorescence Lymph Node Mapping on Improving Diagnostic Values of CT D3 Lymph Node Staging for Right-Sided Colon Cancer. Cancers (Basel) 16. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/cancers16203496\u003c/span\u003e\u003cspan address=\"10.3390/cancers16203496\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu L, Su X, He Z et al (2021) Short-term outcomes of complete mesocolic excision versus D2 dissection in patients undergoing laparoscopic colectomy for right colon cancer (RELARC): a randomised, controlled, phase 3, superiority trial. Lancet Oncol 22:391\u0026ndash;401. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1470-2045(20)30685-9\u003c/span\u003e\u003cspan address=\"10.1016/S1470-2045(20)30685-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 to 6 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Lymph node distribution, Stage III right-sided colon cancer, Right hemicolectomy, Ileocecal resection, Propensity score matching","lastPublishedDoi":"10.21203/rs.3.rs-8757786/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8757786/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cb\u003eBackground\u003c/b\u003e Right hemicolectomy (RHC) and ileocecal resection (ICR) are two widely used surgical approaches for right-sided colon cancer. However, controversies persist regarding their differences in lymph node (LN) dissection completeness, LN metastasis patterns, and long-term oncologic outcomes in patients with stage III disease. This study aimed to compare LN distribution, surgical outcomes, and survival profiles between RHC and ICR in patients with stage III right-sided colon cancer.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMethods\u003c/b\u003e A retrospective analysis was conducted on patients with primary right-sided colon cancer who underwent RHC or ICR at a large oncology center in Japan. Propensity score matching (PSM) was applied to balance baseline characteristics between the two groups at a 1:1 ratio. Comparisons were made regarding LN metastasis rates at different stations (pericolic, intermediate, and apical LNs), surgical outcomes, 5-year overall survival (OS), cancer-specific survival (CSS), relapse-free survival (RFS), and recurrence patterns.\u003c/p\u003e \u003cp\u003e \u003cb\u003eResults\u003c/b\u003e A total of 216 patients in the RHC group and 223 patients in the ICR group were enrolled. After PSM, 185 patients were included in each group. The mean number of excised lymph nodes was significantly higher in the RHC group than in the ICR group both before (36.0\u0026thinsp;\u0026plusmn;\u0026thinsp;15.0 vs. 26.4\u0026thinsp;\u0026plusmn;\u0026thinsp;10.6, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and after PSM (36.0\u0026thinsp;\u0026plusmn;\u0026thinsp;13.8 vs. 26.0\u0026thinsp;\u0026plusmn;\u0026thinsp;10.7, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The D1 nodal metastasis rate was significantly lower in the RHC group both before (13.9% vs. 4.0%, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and after PSM (13.0% vs. 4.3%, p\u0026thinsp;=\u0026thinsp;0.005). No significant differences were observed in 5-year OS (70.8% vs. 62.7%, p\u0026thinsp;=\u0026thinsp;0.137), CSS (77.4% vs. 69.4%, p\u0026thinsp;=\u0026thinsp;0.190), or RFS (72.2% vs. 71.4%, p\u0026thinsp;=\u0026thinsp;0.526) between the two groups after PSM. Multivariate logistic regression analysis revealed that histology type (poorly differentiated, signet ring, or mucinous carcinoma), venous invasion, and pN stage were independent prognostic factors for OS, while pN stage was an independent prognostic factor for RFS. A high carcinoembryonic antigen (CEA) level was identified as a common independent high-risk factor for OS, CSS, and RFS. Recurrence patterns (involving the liver, lung, lymph nodes, peritoneum, etc.) were similar between the two groups (all non-significant [N.S]).\u003c/p\u003e \u003cp\u003eConclusion\u003c/p\u003e \u003cp\u003eFor stage III right-sided colon cancer, RHC achieves a higher number of excised lymph nodes compared with ICR. However, the number of metastatic lymph nodes does not differ significantly between the two groups, and there are no significant differences in long-term oncologic outcomes. The selection of surgical procedure should be individualized based on tumor location, size, and patient-specific factors.\u003c/p\u003e","manuscriptTitle":"Lymph Node Distribution Patterns and Oncologic Outcomes: A Propensity Score-Matched Retrospective Comparison of Right Hemicolectomy versus Ileocecal Resection in Stage III Right-Sided Colon Cancer","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-13 01:12:27","doi":"10.21203/rs.3.rs-8757786/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"75dbed7b-53c6-4d67-872e-c18883161813","owner":[],"postedDate":"February 13th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-02T15:39:39+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-13 01:12:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8757786","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8757786","identity":"rs-8757786","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}