Immune checkpoint inhibitor myocarditis in thymic epithelial tumors: a case report and literature review.

Background: Immunotherapy offers new hope for cancer patients but presents new medical challenges for healthcare workers in terms of the management of immune-related adverse events (irAEs). The clinical data of two patients with advanced thymoma (T) admitted to the Fujian Cancer Hospital who developed fulminant myocarditis after undergoing immunosuppressant therapy were analyzed retrospectively, and the relevant literature was reviewed. This study aims to examine treatment of thymic epithelial tumors (TETs)-associated immune myocarditis. Case Description: An online search was conducted to retrieve relevant full-text articles, and the selected articles were assessed. In total, 13 articles, comprising the data of 113 patients, were included in an analysis to evaluate the efficacy of immunotherapy. Of the 113 patients, 19 had T and 94 had thymic carcinoma (TC). Of the 19 patients with T, 10 (52.6%) achieved a partial response (PR), 8 (42.1%) had stable disease (SD), and 1 (5.3%) had progressive disease (PD). Of the 94 patients with TC, 1 (1.1%) achieved a complete response (CR), 20 (21.3%) achieved a PR, 51 (54.3%) had SD, and 22 (23.4%) had PD. Five articles reported that fulminant myocarditis developed in nine thymic epithelioma patients who were treated with immunosuppressive agents. Two TC patients who presented with fulminant myocarditis were treated with high-dose corticosteroid therapy and underwent pacemaker insertion; none of the patients died of immune myocardial toxicity. However, of the seven T patients who received high-dose corticosteroid therapy and immunoglobulin therapy, and underwent pacemaker implantation, three survived and four died. Conclusions: Immunotherapy has shown promising results in the treatment of patients with refractory or relapsed TETs. Due to their susceptibility to paraneoplastic autoimmunity, TET patients are at a higher risk of developing severe irAEs than patients with other types of cancer. Given the relatively high morbidity and mortality of irAEs, the administration of immune checkpoint inhibitors (ICIs) to treat TETs should be balanced against the clinical response and the precipitation of potentially severe irAEs.