Elderly patient with squamous cell carcinoma of the lung with irAE-associated hidden myocarditis: A case report

Background: Immune checkpoint inhibitors (ICIs) are the standard therapy for various types of cancer. One of them, durvalumab, as a programmed cell death ligand 1 (PD-L1) inhibitor, is commonly used to treat pulmonary malignancies. ^{It has a wide range of known side effects, known as immune-related adverse events (irAEs). Myocarditis as an irAEs is rare but fatal. Currently, there is a paucity of reports on myocarditis as an irAE after durvalumab treatment in elderly patients. Case presentation: The patient was a 79-year-old female with stage Ⅲb squamous cell lung carcinoma and myocarditis as an irAE after durvalumab treatment. She had completed two cycles of carboplatin and TS-1 and received 50 Gy of radiation. After combined chemotherapy and radiotherapy (CCRT), she was administered 10 mg/kg of durvalumab every two weeks as maintenance therapy. After eleven courses over five months of durvalumab, despite the absence of complaints, she experienced a significant decline in cardiac function as observed via echocardiography. Blood tests revealed elevated levels of high-sensitivity cardiac troponin T(hs-cTn). The diagnosis of myocarditis was confirmed through a myocardial biopsy, indicating that it was an irAE following durvalumab therapy. Her myocarditis improved with the discontinuation of durvalumab treatment and the administration of steroid therapy. She has been successfully treated for lung cancer for more than two years without flare-up of myocarditis or lung cancer deterioration, although no treatment for lung cancer has been attempted since the occurrence of myocarditis. Conclusion: In patients on ICIs, especially elderly patients, it is important to pay attention to irAEs and perform periodic electrocardiograms and ECGs, even in asymptomatic persons, for early detection and prognosis improvement.}