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.