Endometriosis-associated Ovarian Cancer: A Distinct Clinical Entity?

The aim of the study was to evaluate the incidence of endometriosis-associated ovarian cancer (EAOC) and compare clinicopathological characteristics and overall survival (OS) between patients with EAOC and those with ovarian cancer not associated with endometriosis.

We identified EAOC among 203 patients with invasive epithelial ovarian cancer who underwent complete surgery at our Institution from January 2004 to March 2014.

EAOC was present in 45 patients. EAOC was significantly more frequently diagnosed at an earlier stage of disease (p=0.038). At a median follow-up time of 32 months, OS among patients with EAOC was significantly longer (p=0.039). However, stratifying by stage, the OS advantage of EAOC was not significant. At multivariate analysis, only stage was an independent prognostic factor for OS (hazard ratio=5.7; 95% confidence interval=1.8-18.6; p=0.003).

EAOC incidence was 22.2%. EAOC appears to be diagnosed at an earlier stage and confers a better OS. However, stratifying by stage, the advantage in survival of EAOC disappears.