縦隔腫瘍に対する治療戦略

Thymoma is the most common tumor of the anterior mediastinum. The rarity of this tumor has somewhat obscured the optimal treatment for this disease. Although the histologic classification of thymoma has remained a subject of controversy for many years, The WHO classification system, which published in 1999, appear to be an advance in our understanding of thymoma. The optimal treatment of thymoma is performed according to its clinical stage. Surgery remains the mainstay of treatment for thymic epithelial tumors. Thymomas also have a high response rate to chemotherapy or radiotherapy. There are several differences between thymoma and thymic carcinoma. Thymoma is a functional tumor, but thymic carcinoma is not. Thymoma has p 53 protein expressions infrequently, and lower incidence of DNA methylation of cancer-related genes comparing with thymic carcinoma. Although thymoma shows cytologically benign, it invades to neighbor organs, disseminates in the thoracic cavity, and rarely metastasizes to the lymph nodes or distant organs. The invasiveness of thymoma is related to increased expression of matrix metalloproteinase and tissue inhibitor of metalloproteinase.