Purpose: Ovarian clear-cell carcinomas (OCCC) are known to be possibly resistant to platinum-based chemotherapy and to have a poorer prognosis with respect to other subtypes of epithelial ovarian cancer (EOC). This study was undertaken to compare response and survival to platinum-based chemotherapy between patients with advanced stage III and IV OCCC and serous EOC (sEOC).
Patients and methods: A retrospective analysis was performed in patients with advanced stage of OCCC treated with first-line platinum-based chemotherapy in the context of several study protocols of the Hellenic Cooperative Oncology Group (HeCOG) between 1/2/1987 and 31/10/2003. The outcome was compared to that of patients with sEOC treated according to the same protocols during the same study period.
Results: One hundred and five patients (35 stage III and IV OCCC, 70 stage III and IV sEOC) treated with platinum-based chemotherapy were analyzed. The overall response rate for OCCC was 45% (complete response 25%) (95% CI, 23.1% to 68.5%) and 81% (complete response 46%) (95% CI, 67.4% to 91.1%) for sEOC. The overall response rate was significantly higher for sEOC (P = 0.008). In the subgroup of stage III patients, the rate of complete responders was higher among sEOC patients (P = 0.023). After a median follow-up of 61.1 months, median survival and time to tumor progression were not significantly different between the two groups (25.1 months [95% CI 11.7 to 38.5 months] versus 49.1 months [95% CI 36.5 to 61.6 months], P = 0.141, 12.0 months [95% CI 6.5 to 17.3 months] versus 18.0 months [95% CI 14.7 to 21.6 months], P = 0.384, respectively).
Conclusion: Patients with OCCC have significantly lower response to platinum-based first-line chemotherapy compared to patients with sEOC. This low response to platinum-based chemotherapy was not translated in significantly shorter survival. The current study outcomes are provocative and suggest that a new strategy for chemotherapy in OCCC should be adopted, possibly one that focuses on new agents without cross-resistance to platinum agents.