Prognosis of Japanese patients with ovarian clear cell carcinoma associated with pelvic endometriosis: Clinicopathologic evaluation

Objective. Ovarian clear cell carcinoma is commonly associated with pelvic endometriosis. We retrospectively evaluated clinicopathological data on the association between ovarian clear cell carcinoma and pelvic endometriosis. Methods. Between 1984 and 1995, we evaluated clinicopathological data on 53 Japanese patients with primary ovarian clear cell carcinoma who had been initially treated at Keio University Hospital. The clinical backgrounds and 5-year survival rates were evaluated. Results. Twenty (37.7%) of the 53 patients had carcinoma accompanied by pelvic endometriosis. These 20 cases were classified as FIGO stage I (n = 13, 65%), stage II (n = 1, 5%), stage III (n = 6, 30%), or stage IV (n = 0). The other 33 cases of ovarian clear cell carcinoma had no evidence of association with endometriosis and were classified as stage I (n = 19, 57.6%), stage II (n = 2, 6.1%), stage III (n = 9, 27.2%), or stage IV (n = 3, 9.1%). The incidence of a positive intraperitoneal cytology in stage Ic was significantly less in the group with endometriosis than in that without the endometriosis (n = 1, 14.3% vs n = 9, 64.3%, P = 0.03). The 5-year survival rate of stage I patients was significantly greater in ovarian clear cell carcinoma with pelvic endometriosis (100%) than in that without it (60%, P < 0.05). Conclusion. Patients having ovarian clear cell carcinoma with pelvic endometriosis exhibited a better prognosis than those without endometriosis, especially those patients with stage I cancer.