680 Sentinel lymph node in endometrial cancer: our experience in the University Hospital 12 de Octubre in Madrid

Introduction/Background* The goal of this study is to review the sentinel lymph node (SLN) in endometrial cancer in the University Hospital 12 de Octubre in Madrid from June 2016 to October 2020. The aim is to know the demographic and clinical features of the patients and to assess the outcomes of SLN in our population with technetium99 (Tc99), indocyanine green (ICG) or blue dye. Methodology Result(s)* From June 2016 to October 2020, 166 patients diagnosed with endometrial cancer underwent surgery in our hospital. In 34.4% (n= 57) of them SLN was performed and included in this review. Demographic and clinical features are shown in table 1. 80.7% (n=46) were classified as low risk endometrial cancer and 19,3% (n=11) as intermediate risk. Laparoscopy was the most frequent approach (96.4%). Median operative time was 203 minutes (IQR, 173 to 249). A combined tracer technique was used in 75.4% cases. Most of them combining Tc99 and ICG (64.9%). Tc99 and blue dye were used in 10.5%. Only one tracer was used in 24.6% (Tc99 5.3%; ICG 17.5%; blue dye 1.8%). Cervix was the only injection site into submucosa and stroma. In 89.5% of the patients, tracer migration was observed. Only 6 patients (10.5%) had no migration. In table 2, detection and migration data of the tracers are shown. One hundred forty-four SLNs were detected. Right side (52.8%) was slightly more frequent than left side (47.2%). Most SLNs were located in external iliac area (40.5%), followed by iliac bifurcation (25.3%), obturator fossa (17.7%) and common iliac (13.9%). In three patients isolated tumor cells were detected (5.2%) and one patient had macrometastases (1.8%). 93% of the patients had no pathological findings in SLNs. Age was significantly higher in the no migration/no detection group in both Tc99 (70 vs 58.5 years; p= 0.01) and ICG/blue dye (72.5 vs 59.4 years; p=0.034). No migration/detection differences were detected for other patient´s features. Conclusion* A combined tracer technique is an effective method to detect SLNs in low-risk endometrial cancer to check lymphatic spread. Older women in our series have lower tracer migration/detection.