Comparative Analysis of Indocyanine Green and Methylene Blue for Sentinel Lymph Node Mapping in V-NOTES Staging Surgery for Endometrial Cancer

Comparative Analysis of Indocyanine Green and Methylene Blue for Sentinel Lymph Node Mapping in V-NOTES Staging Surgery for Endometrial 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 Comparative Analysis of Indocyanine Green and Methylene Blue for Sentinel Lymph Node Mapping in V-NOTES Staging Surgery for Endometrial Cancer Kevser ARKAN, Ali Deniz ERKMEN, Mesut Ali HALISCELIK, Seyhmus TUNC, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6714514/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Oct, 2025 Read the published version in BMC Surgery → Version 1 posted 16 You are reading this latest preprint version Abstract Objective This study aimed to assess the comparative effectiveness of indocyanine green (ICG) and methylene blue in the marking and identification of sentinel lymph nodes (SLN) during SLN biopsy procedures in patients diagnosed with endometrial cancer undergoing staging surgery through vaginal natural orifice transluminal endoscopic surgery (V-NOTES). Methods Consecutive patients with endometrial cancer who underwent staging surgery with V-NOTES at a single center between January 2024 and December 2025 were prospectively included in the study. Patients were randomly divided 1:1 into ICG and methylene blue groups. In the ICG group, ICG (2.5 mg) dissolved in 5 Ml of sterile water was injected subserosally into the cervix. In the methylene blue group, 5 mL of 1% methylene blue solution was injected into the cervix in the same way.The SLN identification rate, number of SLNs identified, bilateral SLN identification rate, surgical time, blood loss, complication rates and histopathologic results were recorded. Findings Eighty (ICG group, n = 40- methylene blue group, n = 40) were included in the study. The SLN identification rate was significantly higher in the ICG group (95%) than in the methylene blue group (82.5%) (p = 0.045). The mean number of SLNs identified in the ICG group (3.2 ± 1.1) was significantly higher than that in the methylene blue group (2.5 ± 0.9) (p = 0.021). The rate of bilateral SLN identification was higher in the ICG group (80%) than in the methylene blue group (65%), but the difference was not statistically significant (p = 0.112). Surgical time, blood loss and complication rates were similar between the two groups. Histopathological examination revealed a similar number of positive SLNs in both groups. Conclusion In the context of sentinel lymph node (SLN) biopsy for staging surgery utilizing V-NOTES in endometrial cancer, indocyanine green (ICG) has demonstrated a superior SLN identification rate and a higher yield of SLNs compared to methylene blue. Given the advantage of real-time imaging, ICG emerges as a promising agent for SLN biopsy in minimally invasive approaches such as V-NOTES. Endometrium cancer sentinel lymph node biopsy indocyanine green methylene blue V-NOTES minimally invasive surgery Figures Figure 1 Figure 2 Key messages What is already known? Minimally invasive surgery and SLNB are feasible and safe for endometrial cancer. ICG and methylene blue are SLN tracers. What this study adds? ICG yields significantly higher SLN identification and more SLNs than methylene blue in V-NOTES staging for endometrial cancer. How might this affect research, practice or policy? ICG shows promise as a superior SLN tracer in V-NOTES for endometrial cancer staging, warranting larger trials to optimize the protocols . Introduction Endometrial cancer (EC) is the most common gynecological cancer in developed countries and staging is essential to facilitate treatment recommendations for adjuvant therapy. ( 1 ) Utilizing sentinel lymph node (SLN) biopsy as part of the minimally invasive staging surgery provides reliable lymph node assessment and significantly lower morbidity compared to lymphadenectomy. ( 2 , 3 ) SLN mapping has less morbidity than traditional extended pelvic and paraaortic lymphadenectomy and has comparable oncological outcomes with significantly lower rates of lymphedema and intraoperative complications. ( 4 ) The concept behind the SLN method is based on the premise that tumor cells metastasize in a predictable manner, stepwise to the SLN prior to arriving at an upper-level lymph node. This method allows for selective dissection of regional lymph nodes, providing a safer surgical alternative with potentially lower morbidity. ( 5 ) Methods for SLN detection usually involve tracers of indocyanine green (ICG) or methylene blue (MB). While indocyanine green (ICG) provides near-infrared fluorescence imaging of lymphatic drainage and higher SLN detection rates in minimally invasive procedures ( 6 , 7 ), methylene blue (MB) is a cheaper dye, easily accessible with purposeful visual staining of the lymphatics, that does not offer a means of real-time imaging( 8 , 9 ). Vaginal natural orifice transluminal endoscopic surgery (V-NOTES) is an innovative surgical approach that is incisionless and has been used successfully in gynecologic oncology locally, including EC staging ( 10 ). Given that this approach has the ability to provide better visualization and access to difficult-to-reach retroperitoneal structures, V-NOTES could improve SLN detection rates and reduce surgical trauma. ( 11 , 12 ) However, there is a lack of data on using dye agents that sequentially compare SLN mapping effectiveness with SLN mapping, leaving us uncertain, which agent is best for SLN mapping in the specific context of V-NOTES. Consequently, we aim to carry out a prospective study to compare the reliability of ICG and MB for SLN mapping of EC patients undergoing V-NOTES staging surgery with respect to SLN detection rates, accuracy, and clinical outcomes. Materials and Methods Study Approval and Design Tis study was designed as a retrospective observational analysis. Te study protocol received approval from the ethics committee of local hospitals before its commencement. Owing to the retrospective nature of the research and the anonymization of patient data, the requirement for informed consent was waived. Te study adhered to the principles outlined in the Helsinki Declaration and the STROBE reporting guidelines Study Design and Patient Selection This retrospective cohort study controlled trial was conducted at Gazi Yasargil Training and Research Hospital, Diyarbakır, Turkey, a single tertiary gynecologic oncology center, over a two-year period from January 2024 to December 2025. The study included consecutive patients with newly diagnosed endometrial cancer. Patients were classified as FIGO stage I-II, and were scheduled to undergo total hysterectomy, bilateral salpingo-oophorectomy (BSO), and SLN biopsy using the V-NOTES approach. Patients with suspected metastatic disease, prior pelvic or paraaortic lymphadenectomy, or known allergies, or hypersensitivity to the marking agents indocyanine ICG or MB were excluded from the study. Application Of Marking Agents ICG Group: After induction of anesthesia, a 1.25 mg/mL solution of ICG was prepared by diluting a vial of ICG (VerDye®, Akorn Pharmaceuticals) containing 25 MG in 20 mL of sterile water. A total of 4–5 mL of this solution was injected into the cervix at the three and nine o'clock positions. There was a protocol for injection as follows: Stromal Injection 1 mL depth of 1 cm, at each side (right and left). Submuccosal Injection 1 mL, in the same positions and targeting the submucosal area. This injection was generally performed after initial laparoscopic exploration to demonstrate the timeliness of the surgical process. At this point, SLNs were visualized using a near-infrared fluorescence imaging system ( i.e., Karl Storz IMAGE1 S™ Rubina® ) in real-time to ascertain proper distribution of drug (Fig. 1 ). MB Group: For patients in the MB group, following induction of anesthesia 4 mL of methylene blue dye was given, 2 mL at the three and nine o'clock positions on the cervix. Injection at the twelve o'clock position was avoided purposely to eliminate the potential for dye migration into the vesicocervicovaginal space and the added danger of complicating dissection of the bladder. To allow for ideal transport of the dye, the surgical process commenced approximately 15 minutes after the cervical injectsion (Fig. 2 ). Surgery All surgical procedures were conducted according to Memorial Sloan Kettering Cancer Center's ( 15 ) standardized procedures. After identifying SLNs, the SLNs were excised, individually tagged, and sent to the pathology laboratory for histopathological evaluation. If there were no SLNs identified or there were suspicious or enlarged lymph nodes, then a side specific or complete pelvic and/or paraaortic lymphadenectomy was performed at the operating surgeon's discretion based on intraoperative findings and clinical judgment. SLN Mapping Patients were positioned in the lithotomy position under general anesthesia. The cervix was held and gently drawn to optimize exposure to the injection sites. In both ICG and MB groups, sub-mucosal injection was conducted at the 3 and 9 o'clock positions of the cervix with the addition of 1 mL of either ICG or MB followed by injection of 1 mL of either at 10 mm depths on either side to facilitate the staining of both deep and superficial lymphatics. For the MB group, a delayed fifteen minutes was observed following the injection of the dye to allow further uptake and staining of the SLN. For the ICG group, there was no wait for the dye because it would rapidly travel through the lymph vessels in the body and, consequently, may stain non-targeted tissues if it was not injected quickly due to the surgery being delayed. During the injection phase, the spread of the dye was observed for fine branches in the sub-mucosal vessels indicating uptake by lymphatics, the marking of nodes by dye, and for identification of lymphatic drainage pathways which were assessed and documented intra-operatively. The SLNs were found in recognized anatomical locations in the pelvic region, mainly in the obturator fossa and in the region between the internal and external iliac veins. The left and right SLNs, that appeared to be poorly draining and symmetrically stained structures, were safely excised. If unilateral or bilateral obvious nodes were not identified, a side-specific or a full pelvic lymphadenectomy procedure was performed. Careful excision was undertaken for any enlarged and suspicious lymph nodes, or if additional secondary SLNs demonstrated any type of methylene blue uptake. All surgical specimens were sent for nodal assessment. Lymph Node Dissection To begin the lymph node dissection, the surgical field was stabilized with a single-tooth tenaculum at the pelvic retroperitoneal space entrance, and to provide sufficient countertraction, the right paracervical vaginal mucosa was grasped about 3 cm lateral to the cervix, while an additional instrument provided lateral tension – approximately 1 cm from the first grasping point. We made a 2 cm vertical vaginal mucosal incision at the 9 o'clock position, noting that the dissection plane was kept inferior to minimize the risk of bladder injury. Using blunt dissection with the surgeon's index finger, we moved through the paracervical connective tissue to gain access to the obturator fossa, keeping a more medial path relative to the ischial part of the pubic bone to avoid neurovascular injury. Upon entering the obturator fossa, the vNOTES port was placed, specifically a 7 cm GelPoint V-Path Transvaginal Access Platform (Applied Medical, Rancho Santa Margarita, CA, USA) while providing CO₂ insufflation at 12 mmHg for improved visualization of the retroperitoneal space. A 30-degree endoscope was introduced through a 10-mm trocar and 10 mm trocars were used for bipolar graspers and a bipolar sealing device to avoid excessive energy-based instrument use along the peritoneum where possible. We identified critical anatomical landmarks first with the obliterated umbilical artery, external iliac vein, ureter, iliac bifurcation, internal and external iliac arteries and veins, and found the obturator nerve. We carefully traced the cervical afferent lymphatic ducts to allow us to dissect out the full extent of the upper paracervical lymphatic drainage region, which included the internal and external iliac and obturator areas. SLNs were excised using advanced bipolar instruments (e.g., LigaSure, Voyant) and extracted transvaginally for pathologic analysis. If we did not identify an SLN or had a suspicious and/or enlarged lymph node, we would perform a side-specific pelvic lymphadenectomy using the same vNOTES technique and explore the contralateral side. If we identified a bulky lymph node on the right side, we typically began with the right-sided SLN dissection, performing left-sided dissection for palliation thereafter. Hysterectomy and Bilateral Salpingo-Oophorectomy (BSO) Upon dissection of the SLN, anterior and posterior colpotomies were completed under the assumption of maintaining the vesicouterine and rectouterine clefts to ultimately limit the potential for contamination of the peritoneal cavity. The cervix was closed in double layer with No. 1 Vicryl sutures to limit the risk of spillage of tumor into the peritoneal cavity during the vNOTES hysterectomy. Upon completing the cervical closure the 9 cm GelPoint V-Path Transvaginal Access Platform (Applied Medical, Rancho Santa Margarita, CA, USA) was utilized to confirm entry into intraperitoneal cavity. The laparoscopy was conducted to explore the abdominal and pelvic cavities for possible adhesions (with potential to create a problematic domain for laparoscopic vNOTES hysterectomy), peritoneal implants, or any other potentially pathological findings. After confirming that the intraperitoneal space had no significant adhesions or suspicious lesions it was time to complete the vNOTES-assisted type 1 hysterectomy and BSO using standard surgical procedures which ensured the complete removal of the uterus, ovaries, and fallopian tubes as previously described ( 16 ). Statistical Analysis Data for this study were sourced from a prospectively maintained institutional database. Clinical and pathologic information was obtained from this prospectively maintained database for demographics of each patient, tumor characteristics, and surgical outcomes into a structured format. The primary outcome was success rate of SLN mapping, which was assessed for overall detection of SLN, detection of bilateral SLN and for specific side. Categorical variables were analyzed using either the chi-squared test or Fisher's exact test when appropriate. Continuous variables were measured using the Student's t-test in the event of normally distributed data, and Mann-Whitney U test in cases of non-normal distribution, determined by the Shapiro-Wilk test for normal distribution. Statistical significance was defined as p < 0.05. Statistical analyses were performed using SPSS software (version 25.0, IBM Corp., Armonk, NY, USA). Results A total of 80 patients were included in the study, with the demographic and clinical characteristics similar between ICG and methylene blue groups, therefore likely minimizing any confounding variables. The mean age was 62.5 ± 8.1 years (ICG) and 61.8 ± 7.5 years (methylene blue) respectively (p = 0.672). Body mass index (BMI) was also similar between groups (ICG: 28.7 ± 4.5 kg/m² vs. methylene blue: 29.1 ± 4.2 kg/m², p = 0.719). Parity was not significantly different between groups (ICG: 2.1 ± 1.3 vs. methylene blue:2.0 ± 1.2, p = 0.805); as well, the post-menopausal proportions were comparable (ICG: 60.0% vs. methylene blue: 62.5%, p = 0.784). The proportions of histologic types (p = 0.553), tumor grades (p = 0.611), and FIGO stages (p = 0.829) were also distributed similarly (Table 1 ). Table 1 Patient Demographic and Clinical Characteristics Feature ICG Group(n = 40) Metilen blue Group (n = 40) p value Age (years, mean ± SD) 62.5 ± 8.1 61.8 ± 7.5 0.672 BMI (kg/m², mean ± SD) 28.7 ± 4.5 29.1 ± 4.2 0.719 Parity (mean ± SD) 2.1 ± 1.3 2.0 ± 1.2 0.805 Postmenopausal (%) 75 (60.0) 78 (62.5) 0.784 Histological Type(%) 0.553 Endometrioid Adenocarcinoma 32 (80.0) 30 (75.0) Serous Adenocarcinoma 5 (12.5) 6 (15.0) Other 3 (7.5) 4 (10.0) Tumor Grade(%) 0.611 1 18 (45.0) 16 (40.0) 2 15 (37.5) 17 (42.5) 3 7 (17.5) 7 (17.5) FIGO Stage(%) 0.829 I 37 (92.5) 37 (92.5) II 3 (7.5) 3 (7.5) While investigating the SLN identification rates, it was identified that the ICG group had a higher overall SLN identification rate (95.0%) compared to the methylene blue group (82.5%) (p = 0.045). The ICG group also had a higher rate of bilateral SLN identification (80.0%) compared to methylene blue (65.0%); however, this was not statistically significant (p = 0.112). The average number of SLNs identified per patient was significantly higher in patients receiving ICG (3.2 ± 1.1) than in patients receiving methylene blue (2.5 ± 0.9, p = 0.021). There were no statistically significant differences in the elapsed time to the first SLN identification (ICG: 8.5 ± 3.2 minutes vs. methylene blue: 9.1 ± 3.8 minutes, p = 0.417) or total operating room time (ICG: 145 ± 35 minutes vs. methylene blue: 152 ± 40 minutes, p = 0.318). Similarly, estimated intraoperative blood loss (ICG: 85 ± 40 mL vs. methylene blue: 92 ± 45 mL, p = 0.489), transfusion requirements (ICG: 5.0% vs. methylene blue: 7.5%, p = 0.652), and overall complication rates (ICG: 12.5% vs. methylene blue: 15.0%, p = 0.721) were similar (Table 2 ). Table 2 Surgical Outcomes and SLN Identification Rates Feature ICG group(n = 40) Metilen Blue Group (n = 40) p value SLN Identification Rate(%) 38 (95.0) 33 (82.5) 0.045 Bilateral SLN Identification Rate(%) 32 (80.0) 26 (65.0) 0.112 Average Number of SLNs Identified 3.2 ± 1.1 2.5 ± 0.9 0.021 Time to First SLN Identification (min) 8.5 ± 3.2 9.1 ± 3.8 0.417 Total Surgical Time (min) 145 ± 35 152 ± 40 0.318 Estimated Blood Loss(mL) 85 ± 40 92 ± 45 0.489 Transfusion Requirement (%) 2 (5.0) 3 (7.5) 0.652 Complication Rate (%) 5 (12.5) 6 (15.0) 0.721 Histopathologic assessment identified SLN metastasis in 8 (21.1%) patients in the ICG group and 7 (21.2%) patients in the methylene blue group, with no statistically significant difference (p = 0.987). In summary, while ICG offers a higher overall rate of SLN identification and a higher average number of SLNs identified per patient than methylene blue, it does not offer a statistically significant earlier time to first SLN identification or an earlier overall surgical time when compared to methylene blue. Discussion Lymph node (LN) involvement is still the primary prognostic factor for women diagnosed with endometrial and cervical cancer. However, due to the low incidence of LN metastasis in early-stage patients, there has been a significant paradigm shift away from more invasive techniques of lymphatic assessment, such as radical pelvic lymphadenectomy or aortic lymphadenectomy, towards less invasive lymphatic assessment techniques (e.g. SLN mapping) over the last couple of decades. The V-NOTES surgical approach has become an alternative to conventional laparoscopic techniques, potentially reducing the morbidity associated with vertical infertility and complete lymphadenectomy. Unlike traditional laparoscopic techniques that approach the lymphatic basin from the periphery of the body, V-NOTES can target the primary lymph nodes directly from the proximal uterus and make the dissection more rapid and targeted ( 17 ). The utilization of ultrastaging techniques in sentinel lymph node biopsy has further optimized nodal assessment by decreasing the complication rate of detecting micrometastases when compared with radical pelvic and/or aortic lymphadenectomy ( 18 , 19 ). Studies documenting the anatomy have established that deep injections into the cervix create lymphatic mappings that effectively target, and include the uterine vessels, parametria, lower uterine segment, and cornual areas ( 20 , 21 ). Additionally, a meta-analysis demonstrated that the only anatomical site that significantly associated with improved ability to identify SLN was cervical injection ( 22 ). Therefore, cervical injection is particularly important in accomplishing successful mapping. The testing we conducted is consistent with this practice and supports cervical dye injection's usefulness for targeting and mapping the lymphatic pathways from the uterus. This study presents information comparing two staining methods, ICG, and MB in women undergoing V-NOTES staging surgery for endometrial cancer. The groups were homogeneous in baseline demographic and clinical characteristics, including BMI. Previous evidence suggests that BMI may be inversely related with SLN mapping success, and may influence the choice of dyeing agent. More specifically, ICG has been reported to perform more successfully in higher BMI and lower-body BMI patients due to better tissue penetration and fluorescence, which may enhance identification of lymphatics in visceral and retroperitoneal fat environments. However, our current study was not designed to address direct effects of BMI; rather, the patient groups were purposefully matched in order to account this potential confounder in analysis. Our results show that ICG had better SLN detection rates and greater average SLNs identified per patient than MB; this is consistent with previous investigations that espouse the benefits of using real-time fluorescence imaging for lymphatic mapping. This likely aided in the easier and accurate identification of SLNs by allowing for clear visualization of the lymphatic flow. While the rate of bilateral identification was greater in the ICG group (80.0% vs. 65.0%), it did not reach statistical significance. Clinically, this is meaningful because accurate identification of bilateral mapping is important for comprehensive nodal staging, particularly given the complex and often asymmetric nature of pelvic lymphatic drainage. Larger multicenter studies will need to confirm this possible advantage. While the identification rates of SLN varied, there were no differences in surgical times, fluid losses, or rates of complications for adverse events between groups, suggesting that ICG does not negatively impact the safety of V-NOTES. Moreover, it worth noting that time to first identify the SLN was not significantly different between groups, indicating that the addition of real-time fluorescent imaging to each of the case workflows did not add significant time to the cases. The histopathologic results show that the rates of SLN with metastasis were similarly observed in both groups (21.1% for ICG vs. 21.2% for MB), which demonstrates a similar sensitivity for detecting metastatic disease ( 15 ). Furthermore, the overall rate of SLN identification as greater for ICG, in totality, this likely indicates a lower false-negative rate, which provides at least some assurance that nodal status is ascertainable. There have been numerous studies comparing SLN biopsy using ICG and MB in either laparoscopic or robotic surgery for endometrial cancer, with mixed results. Whereas some studies demonstrate significantly higher identification when using ICG, others have demonstrated no significant differences between agents ( 25 , 26 ). Our study adds to the ongoing discussion by demonstrating advantages to ICG in the minimally invasive V-NOTES approach and argues that evaluation of ICG should continue to be evaluated on larger scales and validated in larger and multi-center studies. Limitations and Strengths This study has several limitations. First, it was a single-center study and externally valididge may have limited generalizability based on surgeons expertise, demographics of the patients, etc. Second, due to the small sample size, we acknowledge that the statistical power to compare differences in secondary outcomes including complication rates and bilateral SLN identification rates was limited. Furthermore, we report only short-term follow up since we were unable to evaluate the oncologic outcomes (recurrence rates and overall survival) with adequate follow up duration. The study was also limited as we did not account for potential differences in mapping rates based off of BMI when using the two different agents. Finally, there was no cost-effectiveness analysis in this study which may be relevant in light of ICG's role as a new standalone dyeing agent that has potential for use during V-NOTES procedures. The results of this study should be interpreted within the limitations described, but there are also some notable strengths. This may be the first prospective, randomized controlled trial to investigate ICG versus methylene blue in SLN mapping of V-NOTES procedures and provide important initial data for this new surgical technique. The study included a standardized surgical protocol, real-time fluorescence imaging for intra-operative SLN assessment with ICG, and therefore improved the accuracy and consistency of SLN mapping. Furthermore, a relatively homogenous patient cohort may have limited confounders and optimizes the internal validity of the results. Lastly, the study may highlight ICG's positive effect on achieving increased overall SLN mapping rates which may reduce false negative results and improve inconclusive accuracy in order achieve better surgical staging. Conclusion In this prospective, randomized controlled trial, indocyanine green (ICG) had a statistically significantly higher sentinel lymph node (SLN) identification rate and average number of SLNs identified per patient on SLN biopsy compared to methylene blue (MB) in SLN biopsy for V-NOTES staging surgery in endometrial cancer. The real-time fluorescence imaging properties of ICG likely account for its superior performance, allowing for greater accuracy and efficiency with lymphatic mapping. These results provide good evidence that ICG is a viable agent for SLN biopsy in minimally invasive surgical techniques such as V-NOTES. However, larger multicenter studies with greater diversity of patients are warranted in order to validate these results and evaluate continuously its translation into the clinical setting and cost implications. Declarations Ethical Statement, Patient Consent, and Publication Permission This study was conducted in accordance with the ethical principles of the Declaration of Helsinki and its later amendments. The research protocol was reviewed and approved by the Gazi Yasargil Training and Research Hospital Ethics Committee (Approval No. 169, Approval Date: 13/09/2024). All participants provided written informed consent prior to their inclusion in the study, after being fully informed about the study's purpose, procedures, potential risks, and benefits. Patient anonymity and confidentiality were maintained throughout the study. The authors affirm that this manuscript is an original work and has not been previously published nor is it under consideration for publication elsewhere. All authors have reviewed and approved the final version of the manuscript for submission. Acknowledgements Not applicable. Authors’ contributions K.A. and B.C. conceived and designed the study. A.D.E. and M.A.H. collected the relevant data, performed the statistical analyses and prepared the fgures and tables. G.C.C. and S.T. interpreted the results. S.A. critically revised the manuscript for important intellectual content. All authors reviewed and approved the fnal version of the manuscript and agree to be accountable for all aspects of the work. Funding The authors declare that this study was not supported by any external funding source. Data availability Data used in this study are not open to public, but will be available upon motivated request to the corresponding author for purpose of scientifc research. Ethics approval and consent to participate The study protocol was approved by the Ethics Committee of The Gazi Yasargil Training and Research Hospital Ethics Committee accepted the study (Approval No. 169, Approval Date: 13/09/2024), which waived the requirement for informed consent. Consent for publication Not applicable. Competing interests The authors declare no competing interests. Author details Kevser Arkan Diyarbakir Gazi Yasargil Research and Training Hospital, Department Obstetrics and Gynecology, Division of Gynecologic Oncology, Diyarbakir, Turkey Elazığ Road 10.Km Üçkuyular location 21070 Kayapınar / Diyarbakır Email address: [email protected] Phone number: +90 553 647 68 38 Clinical Trial Nuber: Not applicable References Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, et al. Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2021;71:209–49. Maheshwari, A. (2020). Preoperative and intraoperative assesment of myometrial invasion and histological grade section. Gynecologic Oncology, 159, 336. https://doi.org/10.1016/j.ygyno.2020.05.618 Terada S, Tanaka T, Murakami H, Tsuchihashi H, Toji A, Daimon A, et al. 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Transvaginal natural orifice transluminal endoscopic surgery (VNOTES) total retroperitoneal sentinel lymph node biopsy for an endometrial cancer patient with prior colon cancer surgery. In International Journal of Gynecological Cancer (Vol. 31, Issue 10, p. 1386). BMJ. https://doi.org/10.1136/ijgc-2021-002710 Abu-Rustum NR. Sentinel lymph node mapping for endometrial cancer: a modern approach to surgical staging. J Natl Compr Canc Netw. 2014;12(2):288–97. Baekelandt J. Total Vaginal NOTES Hysterectomy: A New Approach to Hysterectomy. J Minim Invasive Gynecol. 2015 Sep-Oct;22(6):1088-94. doi: 10.1016/j.jmig.2015.05.015. Epub 2015 May 22. PMID: 26009278. Granzow JW, Soderberg JM, Kaji AH, et al. Review of current surgical treatments for lymphedema. Ann Surg Oncol. 2014;21:1195–20 Raimond E, Ballester M, Hudry D, et al. Impact of sentinel lymph node biopsy on the therapeutic management of early-stage endometrial cancer: results of a retrospective multicenter study. 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Detection of sentinel lymph nodes in patients with endometrial cancer undergoing robotic-assisted staging: a comparison of colorimetric and fluorescence imaging. Gynecol Oncol. 2012 Jul;126(1):25-9. doi: 10.1016/j.ygyno.2012.04.009. Epub 2012 Apr 13. PMID: 22507531. Della Corte L, Giampaolino P, Mercorio A, Riemma G, Schiattarella A, De Franciscis P, Bifulco G. Sentinel lymph node biopsy in endometrial cancer: state of the art. Transl Cancer Res. 2020 Dec;9(12):7725-7733. doi: 10.21037/tcr.2020.04.21. PMID: 35117375; PMCID: PMC8797296. Eriksson AG, Beavis A, Soslow RA, Zhou Q, Abu-Rustum NR, Gardner GJ, Zivanovic O, Long Roche K, Sonoda Y, Leitao MM Jr, Jewell EL. A Comparison of the Detection of Sentinel Lymph Nodes Using Indocyanine Green and Near-Infrared Fluorescence Imaging Versus Blue Dye During Robotic Surgery in Uterine Cancer. Int J Gynecol Cancer. 2017 May;27(4):743-747. doi: 10.1097/IGC.0000000000000959. PMID: 28375931; PMCID: PMC5404984. Rozenholc A, Samouelian V, Warkus T, Gauthier P, Provencher D, Sauthier P, Gauthier F, Drakopoulos P, Cormier B. Green versus blue: Randomized controlled trial comparing indocyanine green with methylene blue for sentinel lymph node detection in endometrial cancer. Gynecol Oncol. 2019 Jun;153(3):500-504. doi: 10.1016/j.ygyno.2019.03.103. Epub 2019 Mar 20. PMID: 30902369. Jewell EL, Huang JJ, Abu-Rustum NR, Gardner GJ, Brown CL, Sonoda Y, Barakat RR, Levine DA, Leitao MM Jr. Detection of sentinel lymph nodes in minimally invasive surgery using indocyanine green and near-infrared fluorescence imaging for uterine and cervical malignancies. Gynecol Oncol. 2014 May;133(2):274-7. doi: 10.1016/j.ygyno.2014.02.028. Epub 2014 Feb 28. PMID: 24582865; PMCID: PMC5715808. Additional Declarations No competing interests reported. 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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-6714514","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":468208336,"identity":"d33518f8-5170-4070-a598-b16f65d21921","order_by":0,"name":"Kevser ARKAN","email":"data:image/png;base64,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","orcid":"","institution":"Diyarbakir Gazi Yasargil Research and Training Hospital","correspondingAuthor":true,"prefix":"","firstName":"Kevser","middleName":"","lastName":"ARKAN","suffix":""},{"id":468208337,"identity":"b98bc9cb-1ef7-4e0b-b2f0-5a9f9dffcab5","order_by":1,"name":"Ali Deniz ERKMEN","email":"","orcid":"","institution":"Diyarbakir Gazi Yasargil Research and Training Hospital","correspondingAuthor":false,"prefix":"","firstName":"Ali","middleName":"Deniz","lastName":"ERKMEN","suffix":""},{"id":468208338,"identity":"f8cfab42-db6a-4698-be74-a8ef00e2b24a","order_by":2,"name":"Mesut Ali HALISCELIK","email":"","orcid":"","institution":"Diyarbakir Gazi Yasargil Research and Training Hospital","correspondingAuthor":false,"prefix":"","firstName":"Mesut","middleName":"Ali","lastName":"HALISCELIK","suffix":""},{"id":468208339,"identity":"43ba7f7b-6258-4d8c-bc16-dc1c0b556780","order_by":3,"name":"Seyhmus TUNC","email":"","orcid":"","institution":"Diyarbakir Gazi Yasargil Research and Training Hospital","correspondingAuthor":false,"prefix":"","firstName":"Seyhmus","middleName":"","lastName":"TUNC","suffix":""},{"id":468208340,"identity":"9e462483-5ceb-48e1-8e82-e6be3dbc21c5","order_by":4,"name":"Gul CAVUSOGLU COLAK","email":"","orcid":"","institution":"Diyarbakir Gazi Yasargil Research and Training Hospital","correspondingAuthor":false,"prefix":"","firstName":"Gul","middleName":"CAVUSOGLU","lastName":"COLAK","suffix":""},{"id":468208341,"identity":"04891eb0-a2d7-466e-9282-f6405626a171","order_by":5,"name":"Sedat AKGOL","email":"","orcid":"","institution":"Diyarbakir Gazi Yasargil Research and Training Hospital","correspondingAuthor":false,"prefix":"","firstName":"Sedat","middleName":"","lastName":"AKGOL","suffix":""},{"id":468208342,"identity":"c2937fb8-34b1-42b0-a210-77f70e644921","order_by":6,"name":"Behzat CAN","email":"","orcid":"","institution":"Bower Hospital","correspondingAuthor":false,"prefix":"","firstName":"Behzat","middleName":"","lastName":"CAN","suffix":""}],"badges":[],"createdAt":"2025-05-21 08:53:03","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6714514/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6714514/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12893-025-03232-w","type":"published","date":"2025-10-21T16:17:10+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":84305892,"identity":"3efe60e4-c1e2-4096-bbe4-828cc5e4bd99","added_by":"auto","created_at":"2025-06-10 11:24:23","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":316598,"visible":true,"origin":"","legend":"\u003cp\u003eAnatomical view of the right pelvic\u003c/p\u003e\n\u003cp\u003eparavesical area stained with methylene blue following lymph node dissection via retroperitoneal transvaginal approach\u003c/p\u003e\n\u003cp\u003ewith vNOTES. (ECSLN: Efferent channels of the sentinel lymph node, RCIA: Right\u003c/p\u003e\n\u003cp\u003ecommon iliac artery, REIA: Right external iliac artery, REIV: Right external iliac vein,RIIA: Right internal iliac artery, RIIV: Right internal iliac vein, RON: Right obturator nerve, RPM: Right psoas muscle) (Behzat.C et all. 2023)\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6714514/v1/1fee41d6cca5da016df14b1a.png"},{"id":84306102,"identity":"c55d156c-7f51-4b0e-bc22-ec45d3d736ff","added_by":"auto","created_at":"2025-06-10 11:24:34","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":293692,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea-)\u003c/strong\u003e Anatomical view of the right pelvic and \u003cstrong\u003eb-)\u003c/strong\u003eleft pelvic\u003c/p\u003e\n\u003cp\u003eparavesical area stained ICG following lymph node dissection via retroperitoneal transvaginal approach\u003c/p\u003e\n\u003cp\u003ewith vNOTES.\u003c/p\u003e\n\u003cp\u003eLeft: Right pelvic sentinel lymphadenectomy. Right: Left pelvic lymphadenectomy (extra dissection). REIV, right external iliac vein; ON, obtrurator nerve; LEIV, left externai iliac vein, LR, ligamentum rotundum\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6714514/v1/43566acff275a44fb67114f6.png"},{"id":94490586,"identity":"67f8d348-4aa8-496e-816d-61dee9dffd5f","added_by":"auto","created_at":"2025-10-27 17:12:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1567650,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6714514/v1/a3bc576b-068a-4f83-976e-1d618f2ea883.pdf"},{"id":84306045,"identity":"0e96de6d-ea33-471d-82a6-64b1c6137d46","added_by":"auto","created_at":"2025-06-10 11:24:29","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":16019,"visible":true,"origin":"","legend":"","description":"","filename":"highlights.docx","url":"https://assets-eu.researchsquare.com/files/rs-6714514/v1/043de610424a6b3655861d7d.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparative Analysis of Indocyanine Green and Methylene Blue for Sentinel Lymph Node Mapping in V-NOTES Staging Surgery for Endometrial Cancer","fulltext":[{"header":"Key messages","content":"\u003cp\u003e\u003cstrong\u003eWhat is already known?\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMinimally invasive surgery and SLNB are feasible and safe for endometrial cancer. ICG and methylene blue are SLN tracers.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat this study adds?\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eICG yields significantly higher SLN identification and more SLNs than methylene blue in V-NOTES staging for endometrial cancer.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow might this affect research, practice or policy?\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eICG shows promise as a superior SLN tracer in V-NOTES for endometrial cancer staging, warranting larger trials to optimize the protocols\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eEndometrial cancer (EC) is the most common gynecological cancer in developed countries and staging is essential to facilitate treatment recommendations for adjuvant therapy. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) Utilizing sentinel lymph node (SLN) biopsy as part of the minimally invasive staging surgery provides reliable lymph node assessment and significantly lower morbidity compared to lymphadenectomy. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) SLN mapping has less morbidity than traditional extended pelvic and paraaortic lymphadenectomy and has comparable oncological outcomes with significantly lower rates of lymphedema and intraoperative complications. (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e) The concept behind the SLN method is based on the premise that tumor cells metastasize in a predictable manner, stepwise to the SLN prior to arriving at an upper-level lymph node. This method allows for selective dissection of regional lymph nodes, providing a safer surgical alternative with potentially lower morbidity. (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e) Methods for SLN detection usually involve tracers of indocyanine green (ICG) or methylene blue (MB). While indocyanine green (ICG) provides near-infrared fluorescence imaging of lymphatic drainage and higher SLN detection rates in minimally invasive procedures (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e), methylene blue (MB) is a cheaper dye, easily accessible with purposeful visual staining of the lymphatics, that does not offer a means of real-time imaging(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eVaginal natural orifice transluminal endoscopic surgery (V-NOTES) is an innovative surgical approach that is incisionless and has been used successfully in gynecologic oncology locally, including EC staging (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Given that this approach has the ability to provide better visualization and access to difficult-to-reach retroperitoneal structures, V-NOTES could improve SLN detection rates and reduce surgical trauma. (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e) However, there is a lack of data on using dye agents that sequentially compare SLN mapping effectiveness with SLN mapping, leaving us uncertain, which agent is best for SLN mapping in the specific context of V-NOTES.\u003c/p\u003e \u003cp\u003eConsequently, we aim to carry out a prospective study to compare the reliability of ICG and MB for SLN mapping of EC patients undergoing V-NOTES staging surgery with respect to SLN detection rates, accuracy, and clinical outcomes.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Approval and Design\u003c/h2\u003e \u003cp\u003eTis study was designed as a retrospective observational analysis. Te study protocol received approval from the ethics committee of local hospitals before its commencement. Owing to the retrospective nature of the research and the anonymization of patient data, the requirement for informed consent was waived. Te study adhered to the principles outlined in the Helsinki Declaration and the STROBE reporting guidelines\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eStudy Design and Patient Selection\u003c/h3\u003e\n\u003cp\u003eThis retrospective cohort study controlled trial was conducted at Gazi Yasargil Training and Research Hospital, Diyarbakır, Turkey, a single tertiary gynecologic oncology center, over a two-year period from January 2024 to December 2025.\u003c/p\u003e \u003cp\u003eThe study included consecutive patients with newly diagnosed endometrial cancer. Patients were classified as FIGO stage I-II, and were scheduled to undergo total hysterectomy, bilateral salpingo-oophorectomy (BSO), and SLN biopsy using the V-NOTES approach.\u003c/p\u003e \u003cp\u003ePatients with suspected metastatic disease, prior pelvic or paraaortic lymphadenectomy, or known allergies, or hypersensitivity to the marking agents indocyanine ICG or MB were excluded from the study.\u003c/p\u003e\n\u003ch3\u003eApplication Of Marking Agents\u003c/h3\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eICG Group:\u003c/h2\u003e \u003cp\u003eAfter induction of anesthesia, a 1.25 mg/mL solution of ICG was prepared by diluting a vial of ICG (VerDye\u0026reg;, Akorn Pharmaceuticals) containing 25 MG in 20 mL of sterile water. A total of 4\u0026ndash;5 mL of this solution was injected into the cervix at the three and nine o'clock positions. There was a protocol for injection as follows:\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eStromal Injection\u003c/strong\u003e \u003cp\u003e1 mL depth of 1 cm, at each side (right and left).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSubmuccosal Injection\u003c/strong\u003e \u003cp\u003e1 mL, in the same positions and targeting the submucosal area.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eThis injection was generally performed after initial laparoscopic exploration to demonstrate the timeliness of the surgical process. At this point, SLNs were visualized using a near-infrared fluorescence imaging system ( i.e., Karl Storz IMAGE1 S\u0026trade; Rubina\u0026reg; ) in real-time to ascertain proper distribution of drug (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eMB Group:\u003c/h3\u003e\n\u003cp\u003eFor patients in the MB group, following induction of anesthesia 4 mL of methylene blue dye was given, 2 mL at the three and nine o'clock positions on the cervix. Injection at the twelve o'clock position was avoided purposely to eliminate the potential for dye migration into the vesicocervicovaginal space and the added danger of complicating dissection of the bladder. To allow for ideal transport of the dye, the surgical process commenced approximately 15 minutes after the cervical injectsion (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eSurgery\u003c/h2\u003e \u003cp\u003eAll surgical procedures were conducted according to Memorial Sloan Kettering Cancer Center's (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e) standardized procedures. After identifying SLNs, the SLNs were excised, individually tagged, and sent to the pathology laboratory for histopathological evaluation.\u003c/p\u003e \u003cp\u003eIf there were no SLNs identified or there were suspicious or enlarged lymph nodes, then a side specific or complete pelvic and/or paraaortic lymphadenectomy was performed at the operating surgeon's discretion based on intraoperative findings and clinical judgment.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSLN Mapping\u003c/h3\u003e\n\u003cp\u003ePatients were positioned in the lithotomy position under general anesthesia. The cervix was held and gently drawn to optimize exposure to the injection sites. In both ICG and MB groups, sub-mucosal injection was conducted at the 3 and 9 o'clock positions of the cervix with the addition of 1 mL of either ICG or MB followed by injection of 1 mL of either at 10 mm depths on either side to facilitate the staining of both deep and superficial lymphatics.\u003c/p\u003e \u003cp\u003eFor the MB group, a delayed fifteen minutes was observed following the injection of the dye to allow further uptake and staining of the SLN. For the ICG group, there was no wait for the dye because it would rapidly travel through the lymph vessels in the body and, consequently, may stain non-targeted tissues if it was not injected quickly due to the surgery being delayed.\u003c/p\u003e \u003cp\u003eDuring the injection phase, the spread of the dye was observed for fine branches in the sub-mucosal vessels indicating uptake by lymphatics, the marking of nodes by dye, and for identification of lymphatic drainage pathways which were assessed and documented intra-operatively. The SLNs were found in recognized anatomical locations in the pelvic region, mainly in the obturator fossa and in the region between the internal and external iliac veins. The left and right SLNs, that appeared to be poorly draining and symmetrically stained structures, were safely excised.\u003c/p\u003e \u003cp\u003eIf unilateral or bilateral obvious nodes were not identified, a side-specific or a full pelvic lymphadenectomy procedure was performed. Careful excision was undertaken for any enlarged and suspicious lymph nodes, or if additional secondary SLNs demonstrated any type of methylene blue uptake. All surgical specimens were sent for nodal assessment.\u003c/p\u003e\n\u003ch3\u003eLymph Node Dissection\u003c/h3\u003e\n\u003cp\u003eTo begin the lymph node dissection, the surgical field was stabilized with a single-tooth tenaculum at the pelvic retroperitoneal space entrance, and to provide sufficient countertraction, the right paracervical vaginal mucosa was grasped about 3 cm lateral to the cervix, while an additional instrument provided lateral tension \u0026ndash; approximately 1 cm from the first grasping point.\u003c/p\u003e \u003cp\u003eWe made a 2 cm vertical vaginal mucosal incision at the 9 o'clock position, noting that the dissection plane was kept inferior to minimize the risk of bladder injury. Using blunt dissection with the surgeon's index finger, we moved through the paracervical connective tissue to gain access to the obturator fossa, keeping a more medial path relative to the ischial part of the pubic bone to avoid neurovascular injury.\u003c/p\u003e \u003cp\u003eUpon entering the obturator fossa, the vNOTES port was placed, specifically a 7 cm GelPoint V-Path Transvaginal Access Platform (Applied Medical, Rancho Santa Margarita, CA, USA) while providing CO₂ insufflation at 12 mmHg for improved visualization of the retroperitoneal space. A 30-degree endoscope was introduced through a 10-mm trocar and 10 mm trocars were used for bipolar graspers and a bipolar sealing device to avoid excessive energy-based instrument use along the peritoneum where possible.\u003c/p\u003e \u003cp\u003eWe identified critical anatomical landmarks first with the obliterated umbilical artery, external iliac vein, ureter, iliac bifurcation, internal and external iliac arteries and veins, and found the obturator nerve. We carefully traced the cervical afferent lymphatic ducts to allow us to dissect out the full extent of the upper paracervical lymphatic drainage region, which included the internal and external iliac and obturator areas. SLNs were excised using advanced bipolar instruments (e.g., LigaSure, Voyant) and extracted transvaginally for pathologic analysis.\u003c/p\u003e \u003cp\u003eIf we did not identify an SLN or had a suspicious and/or enlarged lymph node, we would perform a side-specific pelvic lymphadenectomy using the same vNOTES technique and explore the contralateral side. If we identified a bulky lymph node on the right side, we typically began with the right-sided SLN dissection, performing left-sided dissection for palliation thereafter.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eHysterectomy and Bilateral Salpingo-Oophorectomy (BSO)\u003c/h2\u003e \u003cp\u003eUpon dissection of the SLN, anterior and posterior colpotomies were completed under the assumption of maintaining the vesicouterine and rectouterine clefts to ultimately limit the potential for contamination of the peritoneal cavity. The cervix was closed in double layer with No. 1 Vicryl sutures to limit the risk of spillage of tumor into the peritoneal cavity during the vNOTES hysterectomy.\u003c/p\u003e \u003cp\u003eUpon completing the cervical closure the 9 cm GelPoint V-Path Transvaginal Access Platform (Applied Medical, Rancho Santa Margarita, CA, USA) was utilized to confirm entry into intraperitoneal cavity. The laparoscopy was conducted to explore the abdominal and pelvic cavities for possible adhesions (with potential to create a problematic domain for laparoscopic vNOTES hysterectomy), peritoneal implants, or any other potentially pathological findings.\u003c/p\u003e \u003cp\u003eAfter confirming that the intraperitoneal space had no significant adhesions or suspicious lesions it was time to complete the vNOTES-assisted type 1 hysterectomy and BSO using standard surgical procedures which ensured the complete removal of the uterus, ovaries, and fallopian tubes as previously described (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eData for this study were sourced from a prospectively maintained institutional database. Clinical and pathologic information was obtained from this prospectively maintained database for demographics of each patient, tumor characteristics, and surgical outcomes into a structured format. The primary outcome was success rate of SLN mapping, which was assessed for overall detection of SLN, detection of bilateral SLN and for specific side.\u003c/p\u003e \u003cp\u003eCategorical variables were analyzed using either the chi-squared test or Fisher's exact test when appropriate. Continuous variables were measured using the Student's t-test in the event of normally distributed data, and Mann-Whitney U test in cases of non-normal distribution, determined by the Shapiro-Wilk test for normal distribution. Statistical significance was defined as p\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Statistical analyses were performed using SPSS software (version 25.0, IBM Corp., Armonk, NY, USA).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 80 patients were included in the study, with the demographic and clinical characteristics similar between ICG and methylene blue groups, therefore likely minimizing any confounding variables. The mean age was 62.5\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1 years (ICG) and 61.8\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5 years (methylene blue) respectively (p\u0026thinsp;=\u0026thinsp;0.672). Body mass index (BMI) was also similar between groups (ICG: 28.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.5 kg/m\u0026sup2; vs. methylene blue: 29.1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2 kg/m\u0026sup2;, p\u0026thinsp;=\u0026thinsp;0.719). Parity was not significantly different between groups (ICG: 2.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 vs. methylene blue:2.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2, p\u0026thinsp;=\u0026thinsp;0.805); as well, the post-menopausal proportions were comparable (ICG: 60.0% vs. methylene blue: 62.5%, p\u0026thinsp;=\u0026thinsp;0.784). The proportions of histologic types (p\u0026thinsp;=\u0026thinsp;0.553), tumor grades (p\u0026thinsp;=\u0026thinsp;0.611), and FIGO stages (p\u0026thinsp;=\u0026thinsp;0.829) were also distributed similarly (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePatient Demographic and Clinical Characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFeature\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eICG Group(n\u0026thinsp;=\u0026thinsp;40)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMetilen blue Group (n\u0026thinsp;=\u0026thinsp;40)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years, mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e62.5\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e61.8\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.672\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m\u0026sup2;, mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.719\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParity (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.805\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostmenopausal (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75 (60.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e78 (62.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.784\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHistological Type(%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.553\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndometrioid Adenocarcinoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e32 (80.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30 (75.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSerous Adenocarcinoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (12.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (15.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOther\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (7.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTumor Grade(%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.611\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (45.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (40.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (37.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17 (42.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (17.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (17.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFIGO Stage(%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.829\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e37 (92.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e37 (92.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eII\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (7.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (7.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWhile investigating the SLN identification rates, it was identified that the ICG group had a higher overall SLN identification rate (95.0%) compared to the methylene blue group (82.5%) (p\u0026thinsp;=\u0026thinsp;0.045). The ICG group also had a higher rate of bilateral SLN identification (80.0%) compared to methylene blue (65.0%); however, this was not statistically significant (p\u0026thinsp;=\u0026thinsp;0.112). The average number of SLNs identified per patient was significantly higher in patients receiving ICG (3.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1) than in patients receiving methylene blue (2.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9, p\u0026thinsp;=\u0026thinsp;0.021). There were no statistically significant differences in the elapsed time to the first SLN identification (ICG: 8.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2 minutes vs. methylene blue: 9.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8 minutes, p\u0026thinsp;=\u0026thinsp;0.417) or total operating room time (ICG: 145\u0026thinsp;\u0026plusmn;\u0026thinsp;35 minutes vs. methylene blue: 152\u0026thinsp;\u0026plusmn;\u0026thinsp;40 minutes, p\u0026thinsp;=\u0026thinsp;0.318). Similarly, estimated intraoperative blood loss (ICG: 85\u0026thinsp;\u0026plusmn;\u0026thinsp;40 mL vs. methylene blue: 92\u0026thinsp;\u0026plusmn;\u0026thinsp;45 mL, p\u0026thinsp;=\u0026thinsp;0.489), transfusion requirements (ICG: 5.0% vs. methylene blue: 7.5%, p\u0026thinsp;=\u0026thinsp;0.652), and overall complication rates (ICG: 12.5% vs. methylene blue: 15.0%, p\u0026thinsp;=\u0026thinsp;0.721) were similar (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSurgical Outcomes and SLN Identification Rates\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFeature\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eICG group(n\u0026thinsp;=\u0026thinsp;40)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMetilen Blue Group (n\u0026thinsp;=\u0026thinsp;40)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSLN Identification Rate(%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38 (95.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33 (82.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.045\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBilateral SLN Identification Rate(%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e32 (80.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26 (65.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.112\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage Number of SLNs Identified\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.021\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime to First SLN Identification (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.417\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal Surgical Time (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e145\u0026thinsp;\u0026plusmn;\u0026thinsp;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e152\u0026thinsp;\u0026plusmn;\u0026thinsp;40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.318\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEstimated Blood Loss(mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e85\u0026thinsp;\u0026plusmn;\u0026thinsp;40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e92\u0026thinsp;\u0026plusmn;\u0026thinsp;45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.489\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransfusion Requirement (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (5.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (7.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.652\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComplication Rate (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (12.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (15.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.721\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eHistopathologic assessment identified SLN metastasis in 8 (21.1%) patients in the ICG group and 7 (21.2%) patients in the methylene blue group, with no statistically significant difference (p\u0026thinsp;=\u0026thinsp;0.987). In summary, while ICG offers a higher overall rate of SLN identification and a higher average number of SLNs identified per patient than methylene blue, it does not offer a statistically significant earlier time to first SLN identification or an earlier overall surgical time when compared to methylene blue.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eLymph node (LN) involvement is still the primary prognostic factor for women diagnosed with endometrial and cervical cancer. However, due to the low incidence of LN metastasis in early-stage patients, there has been a significant paradigm shift away from more invasive techniques of lymphatic assessment, such as radical pelvic lymphadenectomy or aortic lymphadenectomy, towards less invasive lymphatic assessment techniques (e.g. SLN mapping) over the last couple of decades. The V-NOTES surgical approach has become an alternative to conventional laparoscopic techniques, potentially reducing the morbidity associated with vertical infertility and complete lymphadenectomy. Unlike traditional laparoscopic techniques that approach the lymphatic basin from the periphery of the body, V-NOTES can target the primary lymph nodes directly from the proximal uterus and make the dissection more rapid and targeted (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe utilization of ultrastaging techniques in sentinel lymph node biopsy has further optimized nodal assessment by decreasing the complication rate of detecting micrometastases when compared with radical pelvic and/or aortic lymphadenectomy (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). Studies documenting the anatomy have established that deep injections into the cervix create lymphatic mappings that effectively target, and include the uterine vessels, parametria, lower uterine segment, and cornual areas (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). Additionally, a meta-analysis demonstrated that the only anatomical site that significantly associated with improved ability to identify SLN was cervical injection (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). Therefore, cervical injection is particularly important in accomplishing successful mapping. The testing we conducted is consistent with this practice and supports cervical dye injection's usefulness for targeting and mapping the lymphatic pathways from the uterus.\u003c/p\u003e \u003cp\u003eThis study presents information comparing two staining methods, ICG, and MB in women undergoing V-NOTES staging surgery for endometrial cancer. The groups were homogeneous in baseline demographic and clinical characteristics, including BMI. Previous evidence suggests that BMI may be inversely related with SLN mapping success, and may influence the choice of dyeing agent. More specifically, ICG has been reported to perform more successfully in higher BMI and lower-body BMI patients due to better tissue penetration and fluorescence, which may enhance identification of lymphatics in visceral and retroperitoneal fat environments. However, our current study was not designed to address direct effects of BMI; rather, the patient groups were purposefully matched in order to account this potential confounder in analysis.\u003c/p\u003e \u003cp\u003eOur results show that ICG had better SLN detection rates and greater average SLNs identified per patient than MB; this is consistent with previous investigations that espouse the benefits of using real-time fluorescence imaging for lymphatic mapping. This likely aided in the easier and accurate identification of SLNs by allowing for clear visualization of the lymphatic flow. While the rate of bilateral identification was greater in the ICG group (80.0% vs. 65.0%), it did not reach statistical significance. Clinically, this is meaningful because accurate identification of bilateral mapping is important for comprehensive nodal staging, particularly given the complex and often asymmetric nature of pelvic lymphatic drainage. Larger multicenter studies will need to confirm this possible advantage. While the identification rates of SLN varied, there were no differences in surgical times, fluid losses, or rates of complications for adverse events between groups, suggesting that ICG does not negatively impact the safety of V-NOTES. Moreover, it worth noting that time to first identify the SLN was not significantly different between groups, indicating that the addition of real-time fluorescent imaging to each of the case workflows did not add significant time to the cases.\u003c/p\u003e \u003cp\u003eThe histopathologic results show that the rates of SLN with metastasis were similarly observed in both groups (21.1% for ICG vs. 21.2% for MB), which demonstrates a similar sensitivity for detecting metastatic disease (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). Furthermore, the overall rate of SLN identification as greater for ICG, in totality, this likely indicates a lower false-negative rate, which provides at least some assurance that nodal status is ascertainable.\u003c/p\u003e \u003cp\u003eThere have been numerous studies comparing SLN biopsy using ICG and MB in either laparoscopic or robotic surgery for endometrial cancer, with mixed results. Whereas some studies demonstrate significantly higher identification when using ICG, others have demonstrated no significant differences between agents (\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e). Our study adds to the ongoing discussion by demonstrating advantages to ICG in the minimally invasive V-NOTES approach and argues that evaluation of ICG should continue to be evaluated on larger scales and validated in larger and multi-center studies.\u003c/p\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eLimitations and Strengths\u003c/h2\u003e \u003cp\u003eThis study has several limitations. First, it was a single-center study and externally valididge may have limited generalizability based on surgeons expertise, demographics of the patients, etc. Second, due to the small sample size, we acknowledge that the statistical power to compare differences in secondary outcomes including complication rates and bilateral SLN identification rates was limited. Furthermore, we report only short-term follow up since we were unable to evaluate the oncologic outcomes (recurrence rates and overall survival) with adequate follow up duration. The study was also limited as we did not account for potential differences in mapping rates based off of BMI when using the two different agents. Finally, there was no cost-effectiveness analysis in this study which may be relevant in light of ICG's role as a new standalone dyeing agent that has potential for use during V-NOTES procedures.\u003c/p\u003e \u003cp\u003eThe results of this study should be interpreted within the limitations described, but there are also some notable strengths. This may be the first prospective, randomized controlled trial to investigate ICG versus methylene blue in SLN mapping of V-NOTES procedures and provide important initial data for this new surgical technique. The study included a standardized surgical protocol, real-time fluorescence imaging for intra-operative SLN assessment with ICG, and therefore improved the accuracy and consistency of SLN mapping. Furthermore, a relatively homogenous patient cohort may have limited confounders and optimizes the internal validity of the results. Lastly, the study may highlight ICG's positive effect on achieving increased overall SLN mapping rates which may reduce false negative results and improve inconclusive accuracy in order achieve better surgical staging.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn this prospective, randomized controlled trial, indocyanine green (ICG) had a statistically significantly higher sentinel lymph node (SLN) identification rate and average number of SLNs identified per patient on SLN biopsy compared to methylene blue (MB) in SLN biopsy for V-NOTES staging surgery in endometrial cancer. The real-time fluorescence imaging properties of ICG likely account for its superior performance, allowing for greater accuracy and efficiency with lymphatic mapping. These results provide good evidence that ICG is a viable agent for SLN biopsy in minimally invasive surgical techniques such as V-NOTES. However, larger multicenter studies with greater diversity of patients are warranted in order to validate these results and evaluate continuously its translation into the clinical setting and cost implications.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Statement, Patient Consent, and Publication Permission\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was conducted in accordance with the ethical principles of the Declaration of Helsinki and its later amendments. The research protocol was reviewed and approved by the Gazi Yasargil Training and Research Hospital Ethics Committee (Approval No. 169, Approval Date: 13/09/2024).\u003c/p\u003e\n\u003cp\u003eAll participants provided written informed consent prior to their inclusion in the study, after being fully informed about the study\u0026apos;s purpose, procedures, potential risks, and benefits. Patient anonymity and confidentiality were maintained throughout the study.\u003c/p\u003e\n\u003cp\u003eThe authors affirm that this manuscript is an original work and has not been previously published nor is it under consideration for publication elsewhere. All authors have reviewed and approved the final version of the manuscript for submission.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eK.A. and B.C. conceived and designed the study. A.D.E. and M.A.H. collected the relevant data, performed the statistical analyses and prepared the fgures and tables. G.C.C. and S.T. interpreted the results. S.A. critically revised the manuscript for important intellectual content. All authors reviewed and approved the fnal version of the manuscript and agree to be accountable for all aspects of the work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;Funding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that this study was not supported by any external funding source.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;Data availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData used in this study are not open to public, but will be available upon motivated request to the corresponding author for purpose of scientifc research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;Ethics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study protocol was approved by the Ethics Committee of The Gazi Yasargil Training and Research Hospital Ethics Committee accepted the study (Approval No. 169, Approval Date: 13/09/2024), which waived the requirement for informed consent.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;Competing interests\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;Author details\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eKevser Arkan\u003c/p\u003e\n\u003cp\u003eDiyarbakir Gazi Yasargil Research and Training Hospital, Department Obstetrics and Gynecology, Division of Gynecologic Oncology, Diyarbakir, Turkey\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eElazığ Road 10.Km \u0026Uuml;\u0026ccedil;kuyular location 21070 Kayapınar / Diyarbakır\u0026nbsp;\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eEmail address: [email protected]\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePhone number: +90 553 647 68 38\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Trial Nuber:\u003c/strong\u003e Not applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, et al. 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PMID: 35117375; PMCID: PMC8797296.\u003c/li\u003e\n\u003cli\u003eEriksson AG, Beavis A, Soslow RA, Zhou Q, Abu-Rustum NR, Gardner GJ, Zivanovic O, Long Roche K, Sonoda Y, Leitao MM Jr, Jewell EL. A Comparison of the Detection of Sentinel Lymph Nodes Using Indocyanine Green and Near-Infrared Fluorescence Imaging Versus Blue Dye During Robotic Surgery in Uterine Cancer. Int J Gynecol Cancer. 2017 May;27(4):743-747. doi: 10.1097/IGC.0000000000000959. PMID: 28375931; PMCID: PMC5404984.\u003c/li\u003e\n\u003cli\u003eRozenholc A, Samouelian V, Warkus T, Gauthier P, Provencher D, Sauthier P, Gauthier F, Drakopoulos P, Cormier B. Green versus blue: Randomized controlled trial comparing indocyanine green with methylene blue for sentinel lymph node detection in endometrial cancer. Gynecol Oncol. 2019 Jun;153(3):500-504. doi: 10.1016/j.ygyno.2019.03.103. Epub 2019 Mar 20. PMID: 30902369.\u003c/li\u003e\n\u003cli\u003eJewell EL, Huang JJ, Abu-Rustum NR, Gardner GJ, Brown CL, Sonoda Y, Barakat RR, Levine DA, Leitao MM Jr. Detection of sentinel lymph nodes in minimally invasive surgery using indocyanine green and near-infrared fluorescence imaging for uterine and cervical malignancies. Gynecol Oncol. 2014 May;133(2):274-7. doi: 10.1016/j.ygyno.2014.02.028. Epub 2014 Feb 28. PMID: 24582865; PMCID: PMC5715808.\u003c/li\u003e\n\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":"bmc-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bsur","sideBox":"Learn more about [BMC Surgery](http://bmcsurg.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bsur/default.aspx","title":"BMC Surgery","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Endometrium cancer, sentinel lymph node biopsy, indocyanine green, methylene blue, V-NOTES, minimally invasive surgery","lastPublishedDoi":"10.21203/rs.3.rs-6714514/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6714514/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study aimed to assess the comparative effectiveness of indocyanine green (ICG) and methylene blue in the marking and identification of sentinel lymph nodes (SLN) during SLN biopsy procedures in patients diagnosed with endometrial cancer undergoing staging surgery through vaginal natural orifice transluminal endoscopic surgery (V-NOTES).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConsecutive patients with endometrial cancer who underwent staging surgery with V-NOTES at a single center between January 2024 and December 2025 were prospectively included in the study. Patients were randomly divided 1:1 into ICG and methylene blue groups. In the ICG group, ICG (2.5 mg) dissolved in 5 Ml of sterile water was injected subserosally into the cervix. In the methylene blue group, 5 mL of 1% methylene blue solution was injected into the cervix in the same way.The SLN identification rate, number of SLNs identified, bilateral SLN identification rate, surgical time, blood loss, complication rates and histopathologic results were recorded.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFindings\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEighty (ICG group, n = 40- methylene blue group, n = 40) were included in the study. The SLN identification rate was significantly higher in the ICG group (95%) than in the methylene blue group (82.5%) (p = 0.045). The mean number of SLNs identified in the ICG group (3.2 ± 1.1) was significantly higher than that in the methylene blue group (2.5 ± 0.9) (p = 0.021). The rate of bilateral SLN identification was higher in the ICG group (80%) than in the methylene blue group (65%), but the difference was not statistically significant (p = 0.112). Surgical time, blood loss and complication rates were similar between the two groups. Histopathological examination revealed a similar number of positive SLNs in both groups.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the context of sentinel lymph node (SLN) biopsy for staging surgery utilizing V-NOTES in endometrial cancer, indocyanine green (ICG) has demonstrated a superior SLN identification rate and a higher yield of SLNs compared to methylene blue. Given the advantage of real-time imaging, ICG emerges as a promising agent for SLN biopsy in minimally invasive approaches such as V-NOTES.\u003c/p\u003e","manuscriptTitle":"Comparative Analysis of Indocyanine Green and Methylene Blue for Sentinel Lymph Node Mapping in V-NOTES Staging Surgery for Endometrial Cancer","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-10 11:23:51","doi":"10.21203/rs.3.rs-6714514/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-03T18:59:19+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-28T19:24:01+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-25T17:51:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-22T23:51:29+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-12T11:28:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"264347683326593456222071919054233396981","date":"2025-06-10T22:09:52+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-10T06:07:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"287391572169330084605530962665605617555","date":"2025-06-10T00:54:18+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"222927041538486439363081564962140754429","date":"2025-06-08T17:58:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"152801605289601691288211477756377861184","date":"2025-06-06T18:00:30+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"108237337810862617859952234587733472745","date":"2025-06-06T06:59:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"155087540332323281439601411753272771780","date":"2025-06-05T18:20:39+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-05T17:56:52+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-29T11:25:16+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-29T11:22:15+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Surgery","date":"2025-05-21T08:37:05+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bsur","sideBox":"Learn more about [BMC Surgery](http://bmcsurg.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bsur/default.aspx","title":"BMC Surgery","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8373c71b-048e-4211-ab95-cc272ac55f05","owner":[],"postedDate":"June 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-10-27T16:28:01+00:00","versionOfRecord":{"articleIdentity":"rs-6714514","link":"https://doi.org/10.1186/s12893-025-03232-w","journal":{"identity":"bmc-surgery","isVorOnly":false,"title":"BMC Surgery"},"publishedOn":"2025-10-21 16:17:10","publishedOnDateReadable":"October 21st, 2025"},"versionCreatedAt":"2025-06-10 11:23:51","video":"","vorDoi":"10.1186/s12893-025-03232-w","vorDoiUrl":"https://doi.org/10.1186/s12893-025-03232-w","workflowStages":[]},"version":"v1","identity":"rs-6714514","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6714514","identity":"rs-6714514","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}