Added prognostic value of sentinel lymph node mapping in endometrial cancer to molecular subgroups

Treatment approaches for endometrial cancer became more personalized in the last decade, mainly due to two key advancements - sentinel lymph node (SLN) mapping and molecular classification. However, their prognostic interaction remains relatively unexplored.

This retrospective cohort study included patients with endometrial cancer, who underwent surgical treatment including SLN mapping at the Bern University Hospital, Switzerland. Ultrastaging of the SLNs and a molecular analysis on the primary tumor was performed.

The study cohort included 206 patients, of which 197 tumor samples underwent molecular classification. 11.2 % were classified as POLEmut, 25.9 % as MMRd, 46.2 % as NSMP, and 16.8 % as p53abn. Overall, 834 SLN were removed. SLN macrometastasis were most prevalent in patients with p53abn tumors (24.2 %), followed by MMRd (13.7 %), NSMP (5.5 %), and POLEmut (0 %) tumors (p = .006). Mean follow-up time was 70.9 months. SLN macrometastasis was significantly associated with a higher risk of recurrence in the entire study cohort (p > .001) and the NSMP subgroup (p > .001). In the MMRd subgroup, SLN macrometastasis remained a significant predictor of recurrence (p = .030) and disease-specific death (p = .047) in multivariate Cox regression analysis. For patients with p53abn endometrial cancer, there was no association between SLN macrometastasis and risk of recurrence (p = .618) or disease specific death (p = .798).

SLN macrometastasis is an independent predictor of recurrence and disease-specific death in patients with MMRd endometrial cancer. In the subgroup of p53abn endometrial cancers, SLN macrometastasis did not have an added impact on oncological outcome.