[Treatment strategy for thymoma and thymic carcinoma]

Thymoma and thymic carcinoma are neoplasms originating from the epithelial cells of the thymus. Although these tumors should be treated according to the pathological diagnosis and the stage, they have distinct characteristics in the clinical behaviors, and therefore, should be treated separately. The standard treatment strategy has not been established because of the rarity of these tumors, but the recent accumulation of experiences provided some insights into therapeutic method for these tumors. In thymoma, Masaoka staging and completeness of surgical resection are important factors to determine the therapeutic method. Stage I and II thymomas are often good candidates for less invasive approach by endoscopic surgery. Highly invasive stage III thymoma, especially with involvement of the great vessel, is supposed to be treated with preoperative chemotherapy. Postoperative adjuvant therapy after complete resection has not been shown to have significant effect. Stage IVA thymoma patients with pleural dissemination sometimes achieve long-term survival after resection, and even subtotal resection has some value. In thymic carcinomas, patients often appear with advanced stage, and multimodality treatment is more frequently recommended than thymomas. Histological grade of aggressiveness is also an important factor for prognosis. Further study is still required for establishment of the universal approach to these tumors including TNM classification.