Prognostic analysis of ovarian cancer associated with endometriosis

The objective of the study was to evaluate the prognosis of ovarian cancer arising in endometriosis.

We retrospectively compared 42 cases of endometriosis-associated ovarian cancer (EAOC) with 184 cases of ovarian carcinoma without endometriosis (OC).

The median age in the EAOC group was 52 vs 59 years in OC (P < .05). In comparison with OC, the EAOC patients were more likely to have low-grade (21% vs 8%; P = .04) and early-stage tumors (International Federation of Gynecology and Obstetrics I and II combined) (49% vs 24%; P = .002). Clear cell (21% vs 2%) and endometrioid (14% vs 3%) tumors were more frequent in EAOC, whereas mucinous tumors were more prevalent in OC (P = .001). The median survival (199 vs 62 months) and the 5 year survival (62% vs 51%) were better for EAOC when compared with OC (P = .038). After controlling for age, stage, grade, and treatment, association with endometriosis was not an independent predictor of better survival in ovarian cancer.

As such, EAOC has a much better survival rate than OC. This could be explained by the higher prevalence of early-stage and low-grade tumors in EAOC when compared with OC.