Clinical features and drug resistance characteristics of ovarian clear cell adenocarcinoma and analysis of its prognostic factors

OBJECTIVE: To investigate the clinical features and factors involved in the drug resistance and prognosis of ovarian clear cell adenocarcinoma (OCCA). METHODS: Forty-seven OCCA patients and 53 ovarian serous cyst adenocarcinoma (OSCA) patients were included in this study. Their clinical characteristics, drug resistance, and prognostic factors were analyzed. RESULTS: The onset age of OCCA was (49.09 + 11.80) years old, and that of OSCA was (55.51 + 1.38) year old. There were 53.3% (24/45) of OCCA and 98.0% (50/51) of OSCA patients who had elevated CA125 levels. There were 46.8% (22/47) of OCCA patients and 7.5% (4/53) of OSCA patients who suffered from endometriosis (EMS). The percentage of early stage (stage I and stage II) OCCA was 80.9% (38/47), and that of OSCA was 11.3% (6/53). A statistically significant difference was observed on all these aspects (P < 0.05). The percentage of drug resistant OCCA was 26.1% (12/46), and that of OSCA was 24.0% (12/50), with a non-significant difference (P = 0.814).Among the patients with advanced stage disease, the percentage of drug resistance was 87.5% (7/8) for OCCA, while that of OSCA was 25.0% (11/44), showing a statistically significant difference (P = 0.003). Multiple logistic regression analysis revealed that OCCA (OR = 21.774, 95%CI: 2.438 to 194.431) and advanced stage (OR = 58.329, 95%CI: 5.750 to 591.703) were independent risk factors of drug resistance in ovarian epithelial cancers. For the advanced stage patients, the median overall survival time of OCCA and OSCA were 11 and 29 months, respectively, with a statistically significant difference (P = 0.000). Cox survival analysis showed that OCCA, advanced stage, suboptimal surgery, fewer than 6 cycles of chemotherapy and drug resistance were all risk factors of OS in ovarian cancer patients (P < 0.05). CONCLUSIONS: The age of onset in OCCA patients is younger than that of OSCA patients. The proportion of combination with endometriosis (EMS) is higher, and more early stage disease is observed in OCCA patients. The percentage of drug resistant in OCCA is higher, especially in advanced stage patients. The prognosis of advanced stage OCCA patients is poorer than that of OSCA patients in advanced stage.