Sentinel node mapping vs. sentinel node mapping plus back-up lymphadenectomy in high-risk endometrial cancer patients. Results from a multi-institutional study

Objective: Sentinel node mapping (SLN) has replaced lymphadenectomy for staging surgery in apparent early-stage low and intermediate risk endometrial cancer (EC). Only limited data about the adoption of SNM in high risk EC is still available. Here, we evaluate the outcomes of high-risk EC undergoing SNM (with or without back-up lymphadenectomy). Methods: This is a multi-institutional international retrospective study, evaluating data of high-risk (FIGO grade 3 endometrioid EC with myometrial invasion >50% and non-endometrioid histology) EC patients undergoing SNM followed by back-up lymphadenectomy and SNM alone. Results: Chart of consecutive 196 patients were evaluated. The study population included 83 and 113 patients with endometrioid and non-endometrioid EC, respectively. SNM alone and SNM followed by back-up lymphadenectomy were performed in 50 and 146 patients, respectively. Among patients having SNM alone, 14 (28%) were diagnosed with nodal disease. In the group of patients undergoing SNM plus back-up lymphadenectomy 34 (23.2%) were diagnosed with nodal disease via SNM. Back-up lymphadenectomy identified 2 (1%) additional patients with nodal disease (in the para-aortic area). Back-up lymphadenectomy allowed to remove adjunctive positive nodes in 16 (11%) patients. After the adoption of propensity-matched algorithm, we observed that patients undergoing SNM plus back-up lymphadenectomy experienced similar disease-free survival (p = 0.416, log-rank test) and overall survival (p = 0.940, log-rank test) than patients undergoing SLN alone. Conclusions: Although the small sample size, and the retrospective study design this study highlighted that type of nodal assessment did not impact survival outcomes in high-risk EC. Theoretically, back-up lymphadenectomy would be useful in improving the removal of positive nodes, but its therapeutic value remains controversial. Further prospective evidence is needed.