Managing recurrent thymic epithelial tumors after resection: outcomes and role of re-resection

Thymic epithelial tumors (TETs) are rare neoplasms that include thymomas, thymic carcinomas (TCs), and thymic neuroendocrine neoplasms (TNENs). These three tumor categories differ in aggressiveness, the incidence of recurrence after resection, the pattern of recurrence, and survival outcomes. Owing to the tumor's rarity, randomized trials have not been performed in the initial treatment setting. Furthermore, such trials have never been performed in recurrent cases after the initial resection. Thymomas have indolent characteristics, with a wide range of biological spectra compared to TCs and TNENs; therefore, several authors have reported favorable outcomes after re-resection for recurrent thymomas. Common recurrent sites are the local site and pleura, and recurrent disease progresses slowly after detection. Additionally, long-term survivors are sometimes observed after recurrence, and whether re-resections contribute to post-recurrent and cause-specific survival remains unclear. Multimodal therapies are indicated in patients with locally or regionally advanced recurrence, similar to those performed in the initial treatment settings. TCs and TNENs exhibit more aggressive behavior than thymomas. Surgical resection was performed on selected patients who experienced recurrence. Currently, there are no guidelines on selecting patients for re-resection. Therefore, it is most likely that each physician selects based on favorable factors, including the extent of disease, disease-free intervals, and histology. No evidence of nonsurgical treatments, such as radiotherapy or chemotherapy, has yet to be established. This review article summarizes the limited evidence on managing recurrent TETs after resection compared to thymomas, TCs, and TNENs, focusing on re-resection.