Immune checkpoint inhibitor-related myocarditis in thymic epithelial tumors: Recent progress and perspectives

Thymic epithelial tumors (TETs) are rare anterior mediastinal malignancies originating in the thymus with poor outcomes, and standard platinum-based chemotherapy shows limited efficacy for treating metastatic or recurrent disease. In this setting, further improved novel treatment strategies are needed. Immune checkpoint inhibitors (ICIs) are widely applied in clinical practice for cancer therapy and early results of clinical trials have brought notable objective responses and lasting survival benefits to patients with TETs. However, the incidences of immune-related adverse events (irAEs), especially cardiac adverse events, are higher than those of other tumor types. Myocarditis is a rapidly progressive and life-threatening irAE in patients treated with ICIs, thereby hindering the further utilization of ICI in TETs patients. Therefore, this article aims to review the results of case series and clinical trials that evaluated ICIs for the treatment of TETs and to provide an overview of the clinical features of fatal ICI-related myocarditis in TETs. Furthermore, we approach insights into the immunobiology of thymic tumors and focus on revealing the mechanisms of cardiotoxicity in patients with TETs, hoping to provide several valuable insights for maximizing the therapeutic potential of ICIs in TETs.