Surgical outcomes of patients with locally advanced thymic epithelial tumor undergoing induction therapy followed by surgery: a narrative review.

Background and Objective: Thymic epithelial tumors (TETs), including thymomas and thymic cancers, are relatively rare malignancies originating from the thymus. Although complete surgical resection is the cornerstone of treatment for these tumors, the optimal management strategy for locally advanced cases remains uncertain. Neoadjuvant therapies, with their potential to improve the likelihood of complete resection, are promising, particularly in marginally operable cases. However, the current evidence supporting this approach is lacking. This review of the existing literature on the efficacy of induction therapy followed by surgical resection for stage III or IV locally advanced TETs aimed to provide an up-to-date perspective and highlighting directions for future clinical research. Methods: PubMed was searched using the keywords "surgery," "survival", "thymoma", "thymic cancer", and "induction therapy". Relevant articles including case series, retrospective studies, prospective studies, and review articles were reviewed and selected for this comprehensive narrative review. Key Content and Findings: This review included primarily revealed retrospective studies and a limited number of prospective phase II trials on induction therapy followed by surgery for stage III or IV locally advanced TETs. No randomized phase III studies were identified, indicating that a comprehensive evaluation of the benefits of induction therapy on overall survival (OS) has not yet been conducted. Induction therapies for both invasive thymoma and thymic cancer included chemotherapy, radiotherapy, and chemoradiotherapy, with anthracycline-based combination chemotherapies being the primary option. For exclusively invasive thymomas, the median rate of complete surgical resection and the 5-year OS rate were reported as 76% and 85%, respectively. Literature focusing on induction therapy for TETs, which includes both thymoma and thymic cancers, indicates that the rates of complete resection and 5-year OS are 76% and 70%, respectively. Conclusions: Our narrative review of retrospective and prospective studies highlighted promising long-term OS rates in patients with advanced TETs who underwent induction therapy followed by surgical resection. These findings support this multimodal treatment strategy in selected patients with stage III and IV TETs.