Thymic epithelial tumor treatment in Japan: analysis of hospital cancer registry and insurance claims data, 2012–2014

INTRODUCTION: Thymic epithelial tumors are a rare type of neoplasm. Accordingly, it is difficult to perform phase III trials in patients with thymic epithelial tumors, and thus, no standard treatment has been established for these tumors. In this study, we aimed to investigate the current status of thymic epithelial tumor treatment in Japan. METHODS: This retrospective observational study enrolled patients with thymic epithelial tumor whose data were recorded in a nationwide Hospital-based Cancer Registry that was linked with health insurance claims data for the registered patients between 2012 and 2014. The patients’ treatment details were obtained from a health insurance claims database. RESULTS: A total of 813 patients with thymoma and 547 with thymic carcinoma were included in the analysis. Overall, 549 (67.5%) thymoma patients underwent surgical resection alone. Among patients with thymic carcinoma, 230 (42.0%) underwent initial surgery, and 124 (53.9%) received subsequent radiotherapy and chemotherapy. Chemotherapy regimens varied across the hospitals; overall, 21 and 22 regimens were used to treat thymoma and thymic carcinoma, respectively. Platinum-based combination regimens were predominantly selected for both diseases. CONCLUSIONS: This study revealed the real-world patterns of thymic epithelial tumor treatment in Japan. Although the nature of this study did not enable the determination of optimal treatment strategies, the simultaneous analysis of nationwide registry, insurance, efficacy and prognostic data may contribute to the establishment of a standard treatment strategy for rarely occurring cancers such as thymic epithelial tumor.