The role of induction therapy for thymic malignancies: a narrative review

Advanced thymic epithelial tumors pose a clinical dilemma for surgeons and medical oncologists. Given the prognostic importance of obtaining a complete resection, interventions that improve resectability may have profound implications. The documented chemosensitivity and radiosensitivity of thymic tumors present an opportunity to use these therapies in the neoadjuvant setting to reduce tumor burden and improve the likelihood of achieving a complete resection. The current evidence available is limited to institutional case-series, large retrospective multi-institutional databases, and phase II clinical trials. The primary objective of considering induction therapy should be facilitating a complete resection; other endpoints such as down-staging or pathologic response have not been shown to result in meaningful improvements in long-term outcomes. There are certain high-risk tumor characteristics that may aid clinicians in appropriately selecting patients for induction therapy. The selection of candidates for induction therapy should take place in a multidisciplinary tumor board including medical oncologist, surgeon, and radiation oncologist with experience in managing advanced thymic malignancies. Without randomized controlled trials, it is unlikely the thymic medical community will arrive at a consensus on the utility of induction therapy. This review will summarize the existing literature and provide insight into the role of induction therapy for advanced thymic malignancies.