Competency Curve in Sentinel Lymph Node Biopsy in Early-Stage Endometrial Cancer: Prospective Single Institute Study in a Tertiary Care Institute in North East India

Background: Sentinel lymph node biopsy (SLNB) has emerged as a less morbid alternative to complete lymphadenectomy for nodal staging in endometrial cancer. However, its adoption requires institutional validation and assessment of the learning curve. This study evaluated the competency curve for SLNB using CUSUM (cumulative sum) analysis in early-stage endometrial cancer at a tertiary cancer centre in North East India. Methods: A prospective cohort study was conducted between November 2023 and November 2024 including 21 patients with clinically early-stage endometrial carcinoma. SLNB was performed using indocyanine green (ICG) and near-infrared imaging, followed by pelvic lymphadenectomy in all cases as per the MSKCC algorithm. Bilateral SLN detection and confirmation of lymphoid tissue on histopathology defined successful SLN mapping. Empty packet was defined as excised tissue presumed intraoperatively to be nodal but lacking lymphoid elements on final histopathology. CUSUM analysis was used to assess the learning curve for bilateral and successful SLN detection. Results: The median age of patients was 55 years, with median BMI of 28.8 kg/m 2. Laparotomy was performed in 76.2% of cases. At least one SLN was detected in 85.7% (18/21), bilateral SLN mapping in 52.4% (11/21), and overall successful SLN detection in 42.9% (9/21). Failed mapping occurred in 14.3% (3/21). Empty packets were noted in 9.5% (2/21), both in the para-aortic basin. False negative SLN was observed in 1 patient when analysed per patient, but none per hemipelvis. CUSUM analysis showed a significant improvement in bilateral and successful SLN detection after the 9th case (p=0.0014), with plateauing trends after 18 cases. Conclusion: SLNB in early-stage endometrial cancer demonstrates a clear learning curve, with competency improving significantly after 9 cases and plateauing after 18 cases. Empty packet rate and mapping failures highlight the importance of institutional validation. SLNB can be feasibly implemented even in low-resource settings, potentially replacing complete lymphadenectomy after adequate training and validation.