Musculoskeletal adverse reactions after immunotherapy for cancer: A case series.

Immunotherapy has revolutionized cancer treatment. Immune checkpoint inhibitors (ICIs) including antibodies targeting cytotoxic T lymphocyte associated antigen-4 and programmed cell death 1 have been shown to be effective in the treatment of certain types of cancer. The benefit of these therapies is to prolong life expectancy in the case of metastatic malignancies. Rheumatic adverse events are not very common. In the present study, 9 patients were monitored between November 2018 and January 2020. The oncologist, who identified the occurrence of rheumatic toxicities after the treatment with ICIs, evaluated the patients. Only oncological patients with rheumatic manifestations after the start of immunotherapy were included. Toxicity grading was performed by both the oncologist and the rheumatologist, on a scale from 1 to 5 (1, mild; 2, moderate; 3, severe; 4, life-threatening; 5, death related to toxicity). The results showed that rheumatoid factor, which was sampled in each patient, was negative in all cases. Patients were treated with nonsteroidal anti-inflammatory drugs or prednisone depending on the severity of the adverse events. The results varied with the severity of the adverse events. In conclusion, as the number of patients treated with ICIs increases, so will the number of patients presenting with immune-related adverse events (irAEs). The collaboration between oncologists and rheumatologists should be intimate to provide optimal treatment to patients. Musculoskeletal manifestations secondary to ICIs are slightly different from other rheumatologically conditions making diagnosis, treatment and monitoring difficult. Thus, irAEs are new and challenging for oncologists, thus understanding of the pathogenesis and clinical characteristics must be improved for better treatment guidelines.