RT Journal Article SR Electronic T1 Significance of Ovarian Endometriosis on the Prognosis of Ovarian Clear Cell Carcinoma JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP 11 OP 18 DO 10.1097/IGC.0000000000001136 VO 28 IS 1 A1 Park, Jeong-Yeol A1 Kim, Dae-Yeon A1 Suh, Dae-Shik A1 Kim, Jong-Hyeok A1 Kim, Yong-Man A1 Kim, Young-Tak A1 Nam, Joo-Hyun YR 2018 UL http://ijgc.bmj.com/content/28/1/11.abstract AB Introduction The aim of this study was to evaluate the significance of ovarian endometriosis on the prognosis of ovarian clear cell carcinoma (OCCC).Methods Patients with OCCC were divided into 2 groups according to the presence of ovarian endometriosis: group 1, no coexisting ovarian endometriosis; group 2, clear cell carcinoma arising from ovarian endometriosis or the presence of ovarian endometriosis elsewhere in the ovary. Clinicopathologic characteristics, disease-free survival (DFS), and overall survival (OS) were compared between the 2 groups.Results Of 155 patients with OCCC, 77 were categorized into group 1 and 78 into group 2. Group 2 patients were younger than group 1 (median age, 48 vs 51 years; P = 0.005) and had higher incidence of early-stage disease (stage I, 77% vs 58%; P = 0.001) and lower incidence of lymph node metastasis (4% vs 17%; P = 0.008). Group 2 patients were observed to have a significantly higher 5-year DFS (P < 0.001) and OS (P = 0.001) compared with group 1. In stage I disease, group 2 had a significantly higher 5-year DFS (P = 0.004) and OS (P = 0.016) than did group 1. In the multivariate analysis, coexisting endometriosis and advanced International Federation of Obstetrics and Gynecology stage were significant factors for both DFS and OS rates.Conclusions Ovarian clear cell carcinoma with endometriosis was found more frequently in younger women and had a higher incidence of early-stage disease and a lower incidence of lymph node metastasis compared with OCCC without endometriosis. Ovarian endometriosis was associated with improved prognostic factors and a better DFS and OS even in stage I disease. Ovarian endometriosis was an independent prognostic factor for OCCC.