Management of thymic tumors—consensus based on the Chinese Alliance for Research in Thymomas Multi-institutional retrospective studies

Thymic tumors are relatively rare malignancies comparing to other solid tumors in the chest (1). Its incidence is estimated to be at 3.93 per 1,000,000, which is about 1/00 of lung cancer and 1/25 of esophageal cancer in China. And it appears to be higher than that reported from North America, which is only 2.14 per 1,000,000 according to the SEER database. However, in the SEER database, the incidence rate was much higher in Asians (3.74 per 1,000,000) than in Caucasians (1.89 per 1,000,000) and close to the data from China. This implicates that there might be some ethnical and generic difference in thymic tumors. In the meantime, both these two registrations record only ‘malignant tumors’ that are clinically advanced diseases. A large part of early stage, low grade lesions are considered ‘benign tumors’ and thus, not registered. Therefore, the actual incidence of thymic tumors is much under-estimated. With the increasing use of screening for other malignancies such as lung cancer, it can be expected that more early stage thymic tumors would be discovered.