Introduction/Background Positive peritoneal cytology (PPC) in endometrial cancer (EC) has been reported as a risk factor for worse oncologic outcomes, but its prognostic role is unclear for patients with low-risk EC. We investigated the prognostic role of PPC in patient with low-risk EC.

Methodology Patients who underwent primary surgical treatment for EC at Mayo Clinic, Rochester, from 1999 to 2021 were included. The prognostic role of PPC was investigated in the entire cohort and in two subsets: low-risk ECs according to NCCN guidelines [endometrioid, grade 1–2, stage IA] and ESGO/ESTRO/ESP guidelines [same as NCCN guidelines, plus no lymphovascular space invasion (LVSI)]. Univariate and multivariable survival analyses were used to evaluate the association of PPC with recurrence and death.

Results 3517 patients were included in the entire cohort, with 1935 in the NCCN low-risk subgroup and 1849 in the ESGO/ESTRO/ESP low-risk subgroup. PPC was found in 15.9% of the entire population (559/3517), including 8.2% of the NCCN subgroup (158/1935), and 8% of the ESGO/ESTRO/ESP subgroup (148/1849). When looking at the entire cohort, recurrence-free survival (RFS) and overall survival (OS) were significantly worse in patients with PPC [p<0.01]. In the NCCN and ESGO/ESTRO/ESP low-risk subgroups, RFS was worse in patients with PPC [p=0.01 and p=0.04, respectively], but there was no difference in OS. On univariate analysis, age, grade, and PPC were significant predictors of recurrence in both low-risk subgroups. After adjusting for variables listed in table 1, PPC remained independently associated with recurrence in the NCCN low-risk subgroup [p<0.01] and in the ESGO/ESTRO/ESP low-risk subgroup [p=0.04].

Conclusion Patients with PPC had worse survival outcomes in the entire cohort and both low-risk subgroups. This is important information when deciding between offering adjuvant therapy vs surveillance in patients with otherwise low-risk disease.

Disclosures The authors have nothing to disclose.