Prognostic significance of histological grade in clear-cell carcinoma of the ovary: a retrospective study of Korean Gynecologic Oncology Group

Background: This study was to investigate the prognostic significance of clinicopathologic characteristics in patients with clear-cell carcinoma (CCC) of the ovary. Materials and methods: Two hundred and one patients with CCC of the ovary were registered in the Korean Gynecologic Oncology Group. The Korean Gynecologic Pathology Study Group reviewed the pathological slides centrally, using a universal grading system. The prognostic significances of clinicopathologic factors were evaluated by multivariate analysis. Results: Most of the patients were diagnosed at an early stage (stage I, 61.3%), and the overall 5-year survival rate was 57%. Early-stage disease showed a favorable prognosis, but advanced diseases showed poor prognosis. Stage of disease was the only significant prognostic factor on multivariate analysis (P < 0.001). However, universal grade and residual tumor also showed prognostic significance on the forward stepwise likelihood ratio test. There was no survival difference observed between patients treated with paclitaxel-based and those treated with platinum-based combination chemotherapy. Conclusions: The stage, residual tumor, and universal grade were significant prognostic factors in patients with CCC of the ovary. The universal grading system is applicable in determining prognosis of CCC of the ovary. Further clinical trials for optimal chemotherapy are in need.