The Impact of Sentinel Node-Mapping in Staging High-Risk Endometrial Cancer.

Background: This study aimed to determine the impact of sentinel lymph node (SLN)-mapping on the staging of high-risk endometrial cancer (endometrioid grade 3, serous, clear cell, carcinosarcoma, deep myometrial invasion, or angiolymphatic invasion).

Methods: The study analyzed a series of 236 patients treated at AC Camargo Cancer Center from June 2007 to February 2017. The compared 75 patients who underwent SLN-mapping (SLN group) with 161 patients who received pelvic ± para-aortic lymphadenectomy (N-SLN group). Patients with adnexal, peritoneal, or suspicious node metastases were excluded from the study.

Results: The groups did not differ in terms of age, histologic type, or presence of deep myometrial invasion. The overall detection rate for SLNs was 85.3%, and bilateral SLNs were observed in 60% of the patients. Of 20 positive SLNs, 8 (40%) were detected only after immunohistochemistry (IHC). The findings showed an overall sensitivity of 90%, a negative predictive value of 95.7%, and a false-negative predictive value of 4.3%. The SLN group had more pelvic node metastases detected than the N-SLN group (26.7 vs 14.3%; p = 0.02). However, the rate of para-aortic node metastases did not differ between the two groups (13.5 vs 5.6%; p = 0.12). Five patients (3.5%) in the N-SLN group had isolated para-aortic node metastases versus none in the patients with SLN mapped. Additionally, the SLN group received more adjuvant chemotherapy (48 vs 33.5%; p = 0.03).

Conclusions: The data suggest that SLN-mapping identifies more pelvic node metastases than lymph node dissection alone and increases the node detection rate by 12.5% after IHC. Furthermore, no isolated para-aortic node metastases are observed when SLN is detected.