Objective The aim of this study was to report the utility and false-negative rates of sentinel lymph node (SLN) mapping during surgical staging of women with high-grade, apparent uterine-confined endometrial cancer.

Methods This was a single-institution study performed at a high-volume academic center. From December 2012 to December 2015, women with high-grade endometrial cancer (grade 3 endometrioid, serous, clear cell, and carcinosarcoma) underwent SLN mapping via cervical injection followed by robot-assisted total laparoscopic hysterectomy and completion lymphadenectomy. Ultrastaging of SLNs was performed in patients with tumors with any degree of myoinvasion. Patient demographics, SLN test characteristics, treatment, and recurrence outcomes were prospectively evaluated for analysis.

Results Fifty-two patients with high-grade histologic findings underwent SLN mapping followed by completion lymphadenectomy. The median patient age was 64 years, and median body mass index was 31.8 kg/m². Most patients had either serous (46%) or grade 3 endometrioid histology (27%) on preoperative biopsy. Nine patients had nodal metastases, 7 of whom had metastases identified in SLNs. No low-volume nodal metastases were identified on ultrastaging. Two patients had false-negative SLN mapping (22%). After a median follow-up of 15.6 months, 14 recurrences (27%) were diagnosed; all were distant or multisite relapses. Sentinel lymph node mapping did not impact the choice of adjuvant therapy or recurrence risk in node-positive patients.

Conclusions Sentinel lymph node detection of metastases in patients with high-grade endometrial cancer is high, but false-negative results were encountered. More research is needed to determine whether SLN mapping can safely replace systemic lymphadenectomy in women with high-risk histologic findings.