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.