title: Prognostic significance of peritoneal cytology in low-intermediate risk endometrial cancer.
abstract: 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.
authors.affiliation: Dalhousie University, Canada. Electronic address: StephanieA.Scott@nshealth.ca.
authors.forename: S A
authors.initials: SA
authors.lastname: Scott
authors.affiliation: Radboud University, Netherlands.
authors.forename: C
authors.initials: C
authors.lastname: van der Zanden
authors.affiliation: Cancer Surveillance & Outcomes, BC Cancer Agency, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Cai
authors.affiliation: Cancer Surveillance & Outcomes, BC Cancer Agency, Canada; Surgical Oncology Network, BC Cancer Agency, Canada.
authors.forename: C E
authors.initials: CE
authors.lastname: McGahan
authors.affiliation: BC Cancer Agency, Canada; University of British Columbia, Canada.
authors.forename: J S
authors.initials: JS
authors.lastname: Kwon
mesh_terms: D001955:British Columbia / Q000453:epidemiology; D018269:Carcinoma, Endometrioid / Q000453:epidemiology / Q000401:mortality / Q000473:pathology*; D015331:Cohort Studies; D016889:Endometrial Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D009215:Myometrium / Q000473:pathology; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010529:Peritoneal Cavity / Q000473:pathology*; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Adjuvant treatment; Endometrial cancer; Low and intermediate risk; Peritoneal cytology; Prognostic factors