The relationships between cancer and autoimmune rheumatic diseases.

Links between autoimmune rheumatic diseases and cancer continue to be elucidated. In this review, we explore this complex, bidirectional relationship. First, the increased risk of cancer across the breadth of the autoimmune rheumatic diseases is described. The magnitude of risk and types of tumors seen can differ by the type of autoimmune disease, timing of disease course, and even clinical and laboratory features within a particular autoimmune disease, suggesting that targeted cancer screening strategies can be considered. Multiple mechanisms linking autoimmune rheumatic diseases and cancer are discussed, including the development of autoimmunity in the context of naturally occurring anti-tumor immune responses and malignancy arising in the context of inflammation and damage from autoimmunity. Immunosuppression for rheumatic disease can increase risk for certain types of cancers. Finally, immune checkpoint inhibitors, a type of cancer immunotherapy, which cause a variety of inflammatory syndromes of importance to rheumatologists, are reviewed.