Background: Checkpoint inhibitor immunotherapies (CPI) have revolutionised the treatment of malignancies. Aberrant T-cell activation secondary to CPI may lead to immune toxicities, named immune-related adverse effects (irAEs).
Objectives: Describe the range and frequency of rheumatic irAEs, review the serology, compare de novo irAEs to patients who developed a flare of their pre-existing rheumatological condition and determine the severity of rheumatic irAEs and the impact on their oncological treatment.
Methods: This retrospective cohort study at Canberra Health Services identified 49 patients with solid organ malignancies treated at Canberra Health Services with CPI from July 2011 to September 2022 who developed rheumatic irAEs.
Results: The prevalence of rheumatic irAEs was 8.7%. Patients with de novo rheumatic irAEs were diagnosed with inflammatory arthritis, myositis, arthralgia, polymyalgia, Sjogren’s syndrome and connective tissue disease. Patients who experienced a flare of their pre-existing rheumatological condition had been previously diagnosed with rheumatoid arthritis, undifferentiated connective tissue disease and scleroderma. The predominant imaging findings were synovitis and muscle oedema. Most patients had mild to moderate toxicities and 131/334 patients had concurrent irAEs. Most patients were treated with corticosteroids. When rheumatic irAEs necessitated CPI discontinuation, most patients were in remission. No deaths were reported to be secondary to rheumatic irAEs.
Conclusion: Rheumatic irAEs are prevalent and early referral to rheumatology is important in treating irAEs so that CPI can be continued.