Introduction The aim of this study was to evaluate the association between average perinephric fat (APF) and surgical complications and survival in individuals with endometrial cancer (EC).

Methods This is a retrospective cohort study of individuals with EC who underwent surgical staging in a tertiary cancer centre in Canada (2015 – 2021). AFP was measured on pre-operative CT scans. Baseline characteristics, surgical complications and survival data were compared between patients with APF < 2.2 cm and those with AFP ≥ 2.2 cm. Cox proportional hazard model was used to evaluate the association between APF and overall survival (OS) and progression-free survival (PFS).

Results Overall, 297 patients were included. Of whom, n=271 had APF <2.2 cm and n=26 had APF ≥ 2.2 cm. Baseline characteristics are presented in table 1. Patients with APF ≥ 2.2 cm had higher rates of failed sentinel lymph node mapping (31% vs 6%, p<0.001). There were no differences between groups in intraoperative (3% vs 4%, p=0.61) and postoperative complications (14% vs 19%, p=0.71). On univariable analysis, APF was not associated with OS (HR 1.58, 95% CI 0.90–2.78, p=0.11). However, increase in APF was significantly associated with worse PFS (HR 1.49, 95% CI 1.08 -2.06, p=0.02). In a multivariable analysis including age, stage, LVSI and deep myometrial invasion, the association between APF and PFS was not statistically significant (HR 1.35, 95% CI 0.96–1.91, p=0.08).

Conclusion/Implications In this cohort of individuals with EC, there was a trend towards worse PFS with increased APF. However, increased APF did not impact perioperative complications or OS.