Performance of sentinel lymph node (SLN) mapping in high-risk endometrial cancer

Objective While the accuracy of the SLN procedure has been validated in patients with low risk EC, its relevance for high-risk EC remains debated. The aim of this study was to evaluate the accuracy of SLN mapping in patients with high-risk EC. Study Method. We reviewed all patients with high risk EC (grade 3 endometrioid, serous, carcinosarcoma, clear cell and undifferentiated) who underwent primary surgery with SLN mapping followed by pelvic +/− paraaortic lymphadenectomy, between November 2010 and November 2016. Results Among 128 patients who underwent SLN mapping followed by a pelvic lymph node dissection, 41 (32%) had a positive pelvic lymph node. Overall, 48.8% of patients underwent paraaortic node sampling (62/128). Paraaortic lymph node metastasis was identified in 17.7% of patients in whom a para-aortic lymph node dissection was performed (11/62), and all had positive pelvic lymph nodes as well. Successful SLN mapping occurred in 115/128 (89,8%) patients, with a bilateral detection rate at 63.2% (81/128). Positive SLNs were identified in 30.4% of patients (39/128) including 7 isolated tumor cells (ITC), 4 micrometastasis and 28 macrometastasis. When the SLNs were detected bilaterally, only one false negative case occurred, providing a sensitivity and negative predictive value of 95.8% and 98.2% respectively. Conclusion Accurate surgical staging is an important prognostic predictor of survival in patients with endometrial cancer. Given the high sensitivity and high negative predictive value found in our study, we believe that the use of SLN mapping appears to be an appropriate staging procedure in high-risk endometrial cancer.