Endometriosis-associated ovarian malignancy: a retrospective analysis of presentation, treatment, and outcome

To investigate the relationship of age and tumors associated with endometriosis and outcome of different histologies of epithelial ovarian cancer arising from endometriosis.

We identified cases of epithelial ovarian cancers with clear cell, endometrioid, or mixed clear cell and endometrioid histologies from January 2001 to March 2009. Tumors were classified as either "arising in" endometriosis, "associated with" endometriosis or "controls" (not associated with endometriosis). We collected information regarding patient demographics, past medical history, presentation at diagnosis, treatment, and outcome.

Of 140 patients identified, 42 (30.0%) had clear cell, 92 (65.7%) had endometrioid, and 6 (4.3%) had mixed. Of those, 28.6% of tumors were associated with endometriosis (n = 40), 37.1% were arising in endometriosis (n = 52), and 34.3% were controls (n = 48). Premenopausal women had tumors that were more likely arising from or associated with endometriosis as compared to tumors in postmenopausal women (p = 0.005). Premenopausal patients were also more likely to present with early stage disease as compared to postmenopausal women (80.4% vs. 63.6%, p = 0.04) and better overall survival (p < 0.008). Survival analyses of the entire cohort showed that improved survival was associated with stage (p < 0.001), grade (p < 0.001), endometrioid histology (p < 0.005), and with tumors associated with or arising in endometriosis (p < 0.04). Multivariate analysis controlling for menopausal status showed the presence of endometriosis was no longer associated with a survival advantage (p = 0.08).

The association with endometriosis does appear, at least in endometrioid tumors, to provide a survival benefit. Overall, menopausal status, stage, and grade are more powerful variables associated with improved survival.