Rheumatic Immune-Related Adverse Events—A Consequence of Immune Checkpoint Inhibitor Therapy

SIMPLE SUMMARY: Cancer therapy has evolved over the years, immunotherapy being the most used for untreatable malignant tumors. Immune checkpoint inhibitors decrease the ability of tumor cells to escape the immune system. Although immune checkpoint inhibitors have a significant impact in the treatment of cancer, they are associated with various adverse effects, mostly inflammation. The adverse events related to the immune system may affect basically every tissue in the human body, including the digestive tract, endocrine glands, liver, skin, cardiovascular, pulmonary and, also, rheumatic systems. In this review, we address the rheumatic immune-related adverse events related to immunotherapy by depicting the characteristics, diagnostic approach and treatment options. ABSTRACT: The advent of immunotherapy has changed the management and therapeutic methods for a variety of malignant tumors in the last decade. Unlike traditional cytotoxic chemotherapy, which works by interfering with cancer cell growth via various pathways and stages of the cell cycle, cancer immunotherapy uses the immune system to reduce malignant cells’ ability to escape the immune system and combat cell proliferation. The widespread use of immune checkpoint inhibitors (ICIs) over the past 10 years has presented valuable information on the profiles of toxic adverse effects. The attenuation of T-lymphocyte inhibitory mechanisms by ICIs results in immune system hyperactivation, which, as expected, is associated with various adverse events defined by inflammation. These adverse events, known as immune-related adverse events (ir-AEs), may affect any type of tissue throughout the human body, which includes the digestive tract, endocrine glands, liver and skin, with reports of cardiovascular, pulmonary and rheumatic ir-AEs as well. The adverse events that arise from ICI therapy are both novel and unique compared to those of the conventional treatment options. Thus, they require a multidisciplinary approach and continuous updates on the diagnostic approach and management.