Prognostic analysis of ovarian cancer associated with endometriosis

OBJECTIVE: The objective of the study was to evaluate the prognosis of ovarian cancer arising in endometriosis. STUDY DESIGN: We retrospectively compared 42 cases of endometriosis-associated ovarian cancer (EAOC) with 184 cases of ovarian carcinoma without endometriosis (OC). RESULTS: 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. CONCLUSION: 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.