Sentinel lymph node biopsy in early stage endometrial cancer: a Turkish gynecologic oncology group study (TRSGO-SLN-001)

Abstract

Objective: The aim of this multicenter study was to evaluate the feasibility of sentinel lymph node (SLN) mapping in clinically uterine confined endometrial cancer.

Methods: Patients who underwent primary surgery for endometrial cancer with an SLN algorithm were reviewed. Indocyanine green or blue dye was used as a tracer. SLNs and/or suspicious lymph nodes were resected. Side specific lymphadenectomy was performed when mapping was unsuccessful. SLNs were ultrastaged on final pathology.

Results: 357 eligible patients were analyzed. Median age was 59 years. Median number of resected SLNs was 2 (range 1-12) per patient. Minimal invasive and open surgeries were performed in 264 (73.9%) and 93 (26.1%) patients, respectively. Indocyanine green was used in 231 (64.7%) and blue dye in 126 (35.3%) patients. The dyes were injected into the cervix in 355 (99.4%) patients. The overall and bilateral SLN detection rates were 91.9% and 71.4%, respectively. The mapping rates using indocyanine green or blue dye were comparable (P=0.526). There were 43 (12%) patients with lymphatic metastasis. The SLN algorithm was not able to detect 3 of 43 patients who had isolated paraaortic metastasis. After SLN biopsy, complete pelvic lymphadenectomy was performed in 286 (80.1%) patients. Sensitivity and negative predictive value were both 100% for the detection of pelvic lymph node metastases. In addition, 117 (32.8%) patients underwent completion paraaortic lymphadenectomy after SLN biopsy. In these patients, sensitivity for detecting metastases to pelvic and/or paraaortic lymph nodes was 90.3% with a negative predictive value of 96.6%. The risk of non-SLN involvement in patients with macrometastatic SLNs, micrometastatic SLNs, and isolated tumor cells in SLNs were 61.2%, 14.3% and 0%, respectively.

Conclusions: SLN biopsy had good accuracy in detecting lymphatic metastasis. However, one-third of cases with metastatic SLNs also had non-SLN involvement and this risk increased to two-thirds of cases with macrometastatic SLNs. The effect of leaving these nodes in situ on survival should be evaluated in further studies.

Keywords: endometrial neoplasms; lymphatic metastasis; sentinel lymph node.