Combined use of ICG and technetium does not improve sentinel lymph node detection in endometrial cancer: Results of the COMBITEC study

Abstract

ObjectiveThere is scarce evidence available about the benefit of combining technetium (99mTc) and indocyanine green (ICG) for sentinel lymph node (SLN) biopsy in endometrial cancer. The aim of this study was to compare the overall and bilateral pelvic detection rates of SLNs in two retrospective cohorts: ICG exclusive vs. combined ICG+99mTc. MethodsThe COMBITEC study (COMBined ICG and Technetium for SLN detection in Endometrial Cancer) consisted of a multicentre retrospective study (February 2015–June 2020) including patients diagnosed with endometrial atypical hyperplasia or early-stage endometrial carcinoma who underwent SLN biopsy by cervical injection of ICG with or without 99mTc in four different referral centers in Spain. ResultsA total of 180 patients were included, 51% (n = 92) in ICG group and 49% (n = 88) in ICG+99mTc group. Eighty-seven percent of the patients presented endometrioid histology, and over 99% of the procedures were performed by a minimally invasive approach. Both groups were comparable regarding their basal characteristics, except for a higher body mass index in ICG+99mTc group and a bigger proportion of robotic-assisted procedures in ICG group.Overall detection rate was 92.8% without significant differences between groups (ICG: 94.6% vs ICG+99mTc: 90.9%, p = .34). No significant differences were observed neither in bilateral pelvic nor aortic mapping rate. When 99mTc was used, surgical procedures were significantly longer. In 7.3% of mapped patients, at least one positive SLN was found (ICG: 10.3% vs ICG+99mTc: 3.9%, p = .109). Empty node packet rates and number of SLNs retrieved per patient were also similar between cohorts. ConclusionCombining preoperative 99mTc to intraoperative ICG did not improve SLN detection in endometrial cancer, but resulted in longer procedures.