The prognostic significance of stage I ovarian clear cell and endometrioid carcinomas arising from endometriotic cysts: is it a myth?

PURPOSE: The aim of this study was to determine the clinicopathologic features and the prognostic significance of Stage I ovarian clear cell and endometrioid carcinomas arising from endometriotic cysts. MATERIALS AND METHODS: Patients with either Stage I ovarian clear cell or endometrioid carcinoma were divided into three groups. *Group 1: Patients with cancers arising from endometriotic cysts *Group 2: Patients with ovarian and pelvic endometriosis *Group 3: Patients without endometriosis Patient characteristics (overall survival and disease-free survival) were compared between groups. RESULTS: Of the 78 patients who participated in this study, 39 were in group 1, 13 were in group 2, and 26 were in group 3. The mean age in groups 1, 2, and 3 were 46 years, 54 years, and 48 years, respectively (p = 0.39). Tumoral characteristics, including capsule rupture, positive cytology, grade, and the presence of synchronous endometrial cancer were similar in both groups. The 5-year overall survival rate in groups 1, 2, and 3 were 100, 90, and 93%, respectively (p = 0.4). Moreover, the recurrence rates did not differ significantly between groups. Furthermore, subgroup analysis of clear cell carcinoma and endometrioid adenocarcinoma separately showed no effect of endometriosis on disease-free survival (DFS) or overall survival (OS). CONCLUSION: Clear cell or endometrioid ovarian carcinoma arising from ovarian and/or pelvic endometriosis shares the same clinicopathologic characteristics with their counterparts that do not arise from endometriosis and patients have similar overall and disease-free survival.