Comparison of Clinical Characteristic and Prognosis between Ovarian Clear Cell Carcinoma and Serous Carcinoma: A 10-Year Cohort Study of Chinese Patients

OBJECTIVES To compare the clinicopathologic features and prognosis of Chinese patients with ovarian clear cell carcinoma (CCC) and serous carcinoma (SC). METHODS A retrospective cohort study was designed to investigate the clinicopathologic characteristic and prognosis of patients with CCC and SC who were diagnosed and treated in in a tertiary referral center (Peking Union Medical College Hospital) between 1999 and 2009. The Kaplan-Meier method and Cox regression were employed in the survival analysis. RESULTS A total of 504 cases were included in the study, comprising 197 cases of CCC and 307 cases of SC. The mean age of the patients with SC was greater than of CCC patients (3.6±0.94, P<0.001). Patients with CCC were more likely to be early-stage and optimally debulked (P<0.001). Regarding cancer-antigen 125, 22% of the patients with CCC had normal values, and the level was significantly lower than in patients with SC (P<0.001). More CCC patients had platinum-resistant tumors compared with platinum-sensitive disease (45.7% in CCC vs. 61.0% in SC [P=0.008]). The 5-year survival rate was 51.2% in the CCC group vs. 49.8% in the SC group (P=0.428). Patients with advanced CCC had a statistically significant poorer overall survival (OS) compared with their SC counterparts (38.0 vs. 52.0 months; hazard ratio 1.584, 95% confidence interval [CI] 1.167-2.150, P=0.003). However, the advantage of improved progression-free survival (PFS) existed across all stages. CONCLUSIONS Women with ovarian CCC presented at a younger age and early stage. Patients with ovarian CCC also had improved PFS, but they had similar OS compared to patients with SC. However, patients with advanced CCC had decreased survival.