Immune-Related Adverse Events in Cancer Patients Treated with Immune Checkpoint Inhibitors: What Emergency Physicians Need to Know

Checkpoint inhibitors have revolutionized cancer treatments and dramatically improved the patients' prognosis. Unlike conventional cytotoxic chemotherapies, these treatments enhance immunity by restoring the anti-tumor activity of T lymphocytes and can generate immune-related adverse events. These adverse events can affect all organs, with varying degrees of severity, and sometimes, be life-threatening. The onset time can vary greatly but usually occurs in the first few months following the start of immunotherapy. These treatments and their toxicities are not well known to emergency physicians. However, the increasing use of these molecules, in extended broad indications, exposes more and more patients to these toxicities and places emergency physicians on the front line when they occur. The challenge for emergency physicians is to recognize this family of molecules and to consider possible toxicity in the presence of compatible symptoms, not to trivialize certain non-specific symptoms by too easily attributing them to cancer progression, and to consider differential diagnoses, especially infection. Since the diagnosis of toxicity can sometimes be long and complex, close collaboration with oncologists and/or organ specialists is crucial and necessary before starting treatment, which most often relies on corticosteroids and, sometimes, on immunosuppressors. We detail here the immune-related adverse events related to checkpoint inhibitors that are most common and/or severe (gastrointestinal, endocrine, cardiac, pulmonary, neuromuscular, and hepatic), with a pragmatic approach intended for emergency physicians.