Prognostic significance of peritoneal cytology in low-intermediate risk endometrial cancer

There is uncertainty surrounding the prognostic value and clinical utility of peritoneal cytology in endometrial cancer. Our primary objective was to determine if positive cytology is associated with disease-free and overall survival in women treated surgically for endometrial cancer, specifically those with low or intermediate risk disease.

This was a retrospective population-based cohort study of British Columbia Cancer Registry patients who underwent surgery with peritoneal washings for endometrioid-type endometrial cancer from 2003 to 2009. Low risk was defined as Stage IA grade 1 or 2, and intermediate risk defined as Stage IA grade 3, or Stage IB grade 1 or 2 tumours. Five-year overall and disease free-survival were assessed using Kaplan-Meier estimation. Potential covariates including peritoneal cytology, grade, depth of myometrial invasion, LVSI, age, and adjuvant therapy were evaluated in a multivariable Cox proportional hazards model.

There were 849 patients, of whom 370 (43.6%) and 298 (35.1%) had low- and intermediate-risk disease, respectively. Overall, forty-nine (5.8%) patients had positive cytology, including 6 and 9 with low- and intermediate-risk respectively (2.2% within low and intermediate risk combined). Positive peritoneal cytology was not significantly associated with disease-free (HR 3.17, 95% CI 0.91-11.03) or overall survival (HR 1.33, 95% CI 0.47-3.76) in low and intermediate risk patients. Only age and extensive LVSI were associated with lower overall survival (HR 1.10, 95% CI 1.08-1.13, and HR 2.39, 95% CI 1.02-5.61, respectively).

Positive peritoneal cytology was not associated with disease-free and overall survival in women with low and intermediate risk endometrial cancer.