FIGO stage IIIC endometrial cancer identification among patients with complex atypical hyperplasia, grade 1 and 2 endometrioid endometrial cancer: laparoscopic indocyanine green sentinel lymph node mapping versus frozen section of the uterus, why get around the problem?

PURPOSE: To compare two surgical strategies used to identify lymph node metastases in patients with preoperative diagnosis of complex atypical hyperplasia (CAH), grade 1 and 2 endometrial cancer (EC).
METHODS: Data on patients with preoperative diagnosis of CAH, grade 1 and 2 EC undergoing laparoscopic indocyanine green (ICG) sentinel lymph node (SLN) mapping followed by frozen section of the uterus were collected. When risk factors were identified at frozen section, patients were subjected to a systematic lymphadenectomy. False negative (FN) rates, negative predictive values (NPV), positive predictive values (PPV) and correlation with stage IIIC EC were calculated for the systematic lymphadenectomy based on frozen section of the uterus and for the SLN mapping.
RESULTS: Six (9.5%) out of 63 patients had lymph nodal metastases. Based on frozen section of the uterus, 22 (34.9%) and 15 (22.2%) patients underwent a pelvic and a pelvic and paraaortic lymphadenectomy, respectively. Five patients with stage IIIC disease were identified with a FN rate of 16.7% and a NPV and PPV of 97.6 and 27.3%, respectively. Overall and bilateral detection rates of ICG SLN mapping were 100 and 97.6%, respectively; no FN were recorded. The identification of patients with stage IIIC disease with ICG SLN mapping showed a NPV and PPV of 100%. Correlation between indication to lymphadenectomy and stage IIIC disease was poor (κ = 0.244) when based on frozen section of the uterus and excellent (κ = 1) when based on SLN mapping.
CONCLUSIONS: ICG SLN mapping reduces the number of unnecessary systematic lymphadenectomies and the risk of underdiagnosing patients with metastatic lymph nodes.