A prospective validation study of sentinel lymph node mapping for high-risk endometrial cancer.

Objective: Sentinel lymph node (SLN) mapping continues to evolve in the surgical staging of endometrial cancer (EC). The purpose of this trial was to identify the sensitivity, false negative rate (FNR) and FN predictive value (FNPV) of SLN compared to complete pelvic and para-aortic lymphadenectomy (LAD) in women with high-risk EC.

Methods: Women with high-risk EC (grade 3, serous, clear cell, carcinosarcoma) were enrolled in this prospective surgical trial. All patients underwent preoperative PET/CT and intraoperative SLN biopsy followed by LAD. Patients with peritoneal disease on imaging or at the time of surgery were excluded. Patients were evaluable if SLN was attempted and complete LAD was performed.

Results: 123 patients were enrolled between 4/13 and 5/16; 101 were evaluable. At least 1 SLN was identified in 89% (90); bilateral detection 58%, unilateral pelvic 40%, para-aortic only 2%. Indocyanine green was used in 61%, blue dye in 28%, and blue dye and technetium in 11%. Twenty-three pts. (23%) had ≥1 positive node. In 20/23, ≥1 SLN was identified and in 19/20 the SLN was positive. Only 1 patient had bilateral negative SLN and positive non-SLNs on final pathology. Overall, sensitivity of SLN was 95% (19/20), FNR was 5% (1/20) and FNPV was 1.4% (1/71). If side-specific LAD was performed when a SLN was not detected, the FNR decreased to 4.3% (1/23).

Conclusion: This prospective trial demonstrated that SLN biopsy plus side-specific LAD, when SLN is not detected, is a reasonable alternative to a complete LAD in high-risk endometrial cancer.