Prospective study of sentinel lymph node mapping for endometrial cancer.

Objective: To evaluate sentinel lymph node (SLN) mapping for endometrial cancer, using radioisotope and indocyanine green (ICG) injections.

Methods: A prospective study was conducted between April 1, 2014, and December 27, 2017, among women with endometrial cancer, excluding those with suspected peritoneal dissemination and lymph node metastasis, at a University hospital in Kagoshima, Japan. Patients with low-risk endometrial cancer underwent pelvic SLN mapping using uterine cervix radioisotope injections; intermediate/high-risk patients underwent pelvic SLN with/without intraoperative para-aortic SLN mapping with ICG subserosal injections. Primary endpoints were estimated detection rates, sensitivity, and negative predict values (NPV) of SLN mapping.

Results: Of 113 patients evaluated, comprehensive pelvic lymphadenectomy was performed after SLN detection in all patients; additional para-aortic lymphadenectomy was performed in 38 (34%) patients. The detection rates for pelvic SLN (≥1), bilateral pelvic SLN, and para-aortic SLN (≥1) were 96%, 80%, and 55%, respectively. Pelvic and para-aortic lymph node metastasis were found in (10%) (12/113) and 18% (6/33) patients, respectively. Isolated para-aortic lymph node metastasis was not observed. In pelvic SLN analysis, sensitivity was 91% and NPV was 99%. In para-aortic SLN analysis, sensitivity and NPV were 100%.

Conclusion: SLN biopsy may be useful to avoid comprehensive pelvic lymphadenectomy in low-risk patients. In high-risk patients, SLN mapping revealed high detection rates, sensitivity, and NPV, including those for para-aortic SLN.