Thymic carcinoma: A rare cancer requiring special attention

Thymic carcinoma is a rare but highly aggressive, easily metastasizing cancer derived from thymic epithelial cells and has a very poor prognosis. Unlike thymoma, which is usually found because it is associated with paraneoplastic syndrome, thymic carcinoma is almost always found at an advanced stage because patients often have atypical symptoms. There is no known tumor marker for thymic carcinoma screening. Because most tumors are discovered at an advanced stage, the Masaoka staging system, which is widely used for thymoma, is of questionable value for thymic carcinoma. Complete resection of the tumor is the mainstay of treatment and leads to the best survival rate for patients. However, the complete resection rate is only approximately 50% and the recurrence rate after complete resection is high, up to 40%. The role of postoperative radiotherapy or chemotherapy is still controversial. For tumors that cannot be completely resected, the result of debulking surgery is not different from that of a biopsy. The efficacy of preoperative radiotherapy, chemotherapy, or concurrent chemoradiation therapy is still debatable because most studies on these topics were for only a small number of patients and were retrospective in nature. The overall 5-year survival rate for patients with thymic carcinoma is only 30-50%. A prospective randomized study requires multi-center collaboration and the establishment of an optimal treatment protocol to increase the survival rate of patients with thymic carcinoma, for which there is no predictive screening biomarker or a suitable staging system at present.