Clear cell carcinomas of the ovary have poorer outcomes compared with serous carcinomas: Results from a single-center Taiwanese study

Background/purpose: To compare the clinical outcomes of Taiwanese patients with ovarian clear cell carcinomas (CCCs) and serous carcinomas (SCs). Methods: We retrieved the clinical records of women with epithelial ovarian cancer (Stage I–IV) who received primary surgeries between 2000 and 2013. Cancer-specific survival (CSS), progression-free survival, and survival after recurrence (SAR) of CCC and SC patients were retrospectively compared. Multivariate analysis was used to identify the independent predictors of survival. Results: Of 891 women diagnosed with epithelial ovarian cancer, 169 CCCs and 351 high-grade SCs were analyzed. The 5-year CSS rates of CCC patients were significantly lower than those of SC for both Stage III (22.3% vs. 47.3%, p = 0.001) and Stage IV (0% vs. 24.4%, p = 0.001) disease. In the absence of gross residual malignancies, the 5-year CSS rate was better for CCC (82.3%) than SC (75.2%, p = 0.010). The 5-year SAR rate was significantly lower for CCC than SC (14.3% vs. 24.4%, p = 0.002). Old age and residual malignancies were independent prognostic factors for CSS in the entire cohort of CCC patients. In the subgroup of Stage I CCC, positive cytology was identified as the only adverse prognostic factor for CSS. Conclusion: The clinical outcomes of CCC are generally poorer than SC. Complete cytoreduction to no gross residual disease should be ideally achieved in CCC patients. A greater understanding of the molecular pathogenesis of CCC may lead to tailored therapies, ultimately optimizing outcomes.