Purpose: Thymic malignancies, comprising thymoma and thymic carcinoma, are rare. Consequently, optimal chemotherapy for advanced thymic malignancies remains controversial. Platinum-based chemotherapy is currently the consensus treatment based on the results of single-arm phase II trials and retrospective investigations. However, comparison of cisplatin-based and carboplatin-based chemotherapy has yet to be undertaken; the effectiveness of the addition of anthracycline also remains uncertain.
Methods: In the present study, clinical trials and retrospective data regarding platinum-based chemotherapy were analyzed. The endpoint was the response rate to each chemotherapy. For advanced thymoma, we compared platinum with anthracycline-based chemotherapy and platinum with non-anthracycline-based chemotherapy. For advanced thymic carcinoma, anthracycline-based versus non-anthracycline-based chemotherapy and carboplatin-based versus cisplatin-based chemotherapy were compared. This analysis included a retrospective study of response of advanced thymic carcinoma to irinotecan and cisplatin in our institution.
Results: The response rate for the 314 patients from 15 studies with advanced thymoma, including both prospective and retrospective data, was 69.4% [95% confidence interval (CI) 63.1-75.0%] for platinum with anthracycline-based chemotherapy and 37.8% (95% CI 28.1-48.6%; p < 0.0001) for platinum with non-anthracycline-based chemotherapy. The response rates after anthracycline-based and non-anthracycline-based chemotherapy for advanced thymic carcinoma were similar (41.8 vs. 40.9%; p < 0.91), whereas the response rates after cisplatin-based and carboplatin-based chemotherapy for advanced thymic carcinoma differed significantly (53.6 vs. 32.8%; p = 0.0029) in 206 patients from 10 studies.
Conclusions: Platinum with anthracycline-based chemotherapy is an optimal combination for advanced thymoma. For advanced thymic carcinoma, cisplatin-based chemotherapy may be superior to carboplatin-based chemotherapy.