Abstract
Treatment with immune checkpoint inhibitors is effective in various cancers, but may be associated with immune-mediated side effects in other organs. Among the more common ones is gastrointestinal tract involvement, especially colitis. In most patients, colitis is mild or responds to corticosteroid treatment. A smaller proportion of patients, more often those treated with cytotoxic T lymphocyte antigen-4 inhibitors, may have a more severe course of colitis, even life-threatening complications. In these patients, prompt action, timely diagnosis with endoscopic evaluation and early treatment with high-dose corticosteroids and, if ineffective, rescue therapy with biologic agents such as infliximab and vedolizumab are needed. We present three cases from our clinical practice, data on incidence and clinical presentation, current recommendations regarding diagnostic approach and treatment of immune checkpoint inhibitors induced colitis.