Severe immune-related hepatitis and myocarditis caused by PD-1 inhibitors in the treatment of triple-negative breast cancer: a case report.

Background: Triple-negative breast cancer (TNBC) is a subtype of breast cancer that is defined clinically by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (Her-2) expression. Due to its unresponsiveness to endocrine or targeted therapies, the clinical prognosis of TNBC is very poor. In recent years, research into immune checkpoint inhibitors (ICIs) has led to significant progress in the treatment of TNBC. A large amount of immune-related adverse events (irAEs), including skin, gastrointestinal, pulmonary, hepatic, cardiovascular, renal and endocrine adverse events, occur in clinical application owing to the widespread use of programmed death-1 (PD-1) inhibitors, although it is rarer to experience two irAEs simultaneously. The simultaneous occurrence of two irAEs increases the difficulty of diagnosis and treatment. Case Description: In this case report, a 51-year-old TNBC woman with a background of modified radical mastectomy 3 years ago was diagnosed with axillary lymph node metastasis. This postoperative recurrent TNBC patient received chemotherapy combined with PD-1 inhibitors, resulting in severe immune-related hepatitis and myocarditis. The patient resolved after treatment with methylprednisolone, interruption of chemotherapy, and discontinuation of immunotherapy. The dosage of methylprednisolone gradually reduced from 80 to 4 mg/day with the improvement of liver function and cardiac function. She completed chemotherapy after recovering from irAEs and followed up for stable disease (SD) until 1st March 2021. Conclusions: With the widespread use of ICIs, the incidence of irAEs has also increased. Early detection and treatment of irAEs presents a new challenge to clinicians. It is the first case report about two severe irAEs in postoperative recurrent TNBC patient after received chemotherapy combined with PD-1 inhibitors. This case illustrates the severe toxicity caused by ICIs which suggests more attention should be paid to early prevention, early diagnosis, and appropriate management of irAEs. Multidisciplinary discussions should be undertaken to improve patient prognosis.