Isolated tumor cells identified by sentinel lymph node mapping in endometrial cancer: Does adjuvant treatment matter?

OBJECTIVE: To evaluate the outcome and the role of adjuvant treatment in the management of patients with endometrial cancer and isolated tumor cells (ITCs) identified by SLN mapping.

METHODS: This single center study identified all patients undergoing hysterectomy, salpingo-oophorectomy, lymphadenectomy and SLN mapping for endometrial cancer between November 2010 and December 2015. Data was prospectively collected. Progression-free survival was analyzed according to the Kaplan-Meier method and compared using the log-rank test.

RESULTS: A total of 519 patients were included. Overall, 85 patients (16.4%) were found to have SLN metastases of which 43 (51%) were macrometastasis, 11 (13%) micrometastasis (MM) and 31 (36%) ITC. Eleven (35%) of patients with ITCs received adjuvant chemotherapy±whole pelvic radiation therapy (WPRT), 10 (32%) received WPRT, and 10 (32%) received either no adjuvant treatment or vault brachytherapy (VBT) only. ITC patients received significantly less chemotherapy (p=0.0001) and WPRT (p=0.007) compared to patients with macrometastasis. Of note, ITC were not considered node positive in our study. With a median follow-up of 29months (range: 0-67), the progression free survival (PFS) at 3-years for the ITC patients was 95.5%, similar to node negative (87.6%) and micrometastasis patients (85.5%), but statistically better than patients with macrometastasis (58.5%) (p=0.0012). Only 1/31 patient with ITC recurred (IB, 7cm carcinosarcoma) despite adjuvant treatments. None of the ITC patients with endometrioid histology recurred (0/28) and none of the ITC patients who did not receive adjuvant treatment or VBT recurred (0/10).

CONCLUSIONS: Patients with endometrial cancer found to have SLN ITCs have an excellent outcome. The use of adjuvant treatment should be tailored to uterine factors and histology and not solely based on the presence of ITCs. Patients with ITCs and otherwise low-risk uterine disease probably derive little benefit from receiving additional treatments. More studies are needed to confirm our results.