Long-term follow-up and prognostic factor analysis in clear cell adenocarcinoma of the ovary

Background and Objectives: There were a few reports of a large number of patients with clear cell adenocarcinoma (CCA) of the ovary because of the low incidence of CCA. This study compared the clinical factors affecting long-term survival of patients with CCA to those with serous cystadenocarcinoma (SCA). Methods: One hundred and seventy-eight CCA and 311 SCA patients treated between 1987 and 2000 were retrospectively evaluated. Differences in survival rates were calculated using log-rank test and Cox's proportional hazards analysis was used to identify independent prognostic factors. Results: The ratio of stage I was significantly higher than that of SCA. There was no significant difference of 8-year survival rate in each stage between CCA and SCA. However, the patients with stage IIIb or IIIc CCA showed significantly worse prognosis than those with SCA. Positive peritoneal or ascitic cytology, the presence of residual tumor, more than 100 ml ascites were demonstrated to have the significant impact on survival by univariate analysis. Multivariate analysis demonstrated that stage, more than 100 ml ascites, and the presence of residual tumor were significant prognostic factors of CCA overall survival. Conclusions: Distribution of stage and substage differed between CCA and SCA in this study. Thus, substaging is quite important for comparison of prognoses between histologies, and CCA showed poorer prognoses than serous adenocarcinoma in stages IIIb and IIIc.