Clinico-pathological significance of suspicious peritoneal cytology in endometrial cancer.

Background And Objectives: Suspicious peritoneal cytology refers to the result of peritoneal cytology testing that is insufficient in either quality or quantity for a definitive diagnosis of malignancy. This study examined characteristics and survival outcomes related to suspicious peritoneal cytology in endometrial cancer.

Methods: A population-based retrospective study by querying the National Cancer Institute's Surveillance, Epidemiology, and End Results Program was conducted. A total of 41,229 women with Stage I-III endometrial cancer who had peritoneal cytologic sampling at hysterectomy from 2010 to 2016 were examined. A Cox proportional hazard regression model and a competing risk analysis with Fine-Gray model were fitted to assess survival outcome related to suspicious peritoneal cytology.

Results: Suspicious peritoneal cytology was seen in 702 (1.7%) cases. In multivariable models, suspicious peritoneal cytology was associated with increased risk of endometrial cancer mortality (subdistribution-hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.29-2.20, p < 0.001) and all-cause mortality (adjusted-HR: 1.55, 95% CI: 1.27-1.90, p < 0.001) compared with negative peritoneal cytology. Sensitivity analysis demonstrated that suspicious peritoneal cytology had discrete overall survival improvement compared with malignant peritoneal cytology in a propensity score weighting model (HR: 0.85, 95% CI: 0.72-0.99, p = 0.049).

Conclusion: Our study suggests that suspicious peritoneal cytology may be a prognostic factor for decreased survival in endometrial cancer.