Identifying Patients at Risk for Immune Checkpoint Inhibitor-Induced Colitis: Evidence From a Real-World Oncology Cohort.

Immune checkpoint inhibitors (ICIs) have significantly improved outcomes across multiple malignancies but are associated with immune-related adverse events, including colitis. Although generally uncommon, ICI-induced colitis can lead to significant morbidity and treatment interruption, and data on its incidence and risk factors in the Middle East remain limited. We conducted a retrospective study of adult cancer patients treated with ICIs at a tertiary care center between December 2018 and March 2023. Clinical and treatment-related variables were collected, and univariable and multivariable logistic regression analyses were performed to identify predictors of colitis. Among 784 patients, 19 (2.4%) developed ICI-related colitis. Most cases were moderate to severe, and 57.9% required hospitalization, with a median length of stay of 7 days. All patients had advanced disease. Endoscopic evaluation, performed in 42.1% of patients, demonstrated heterogeneous disease distribution. ICI therapy was discontinued in 78.9% of patients and resumed in 36.8%. Corticosteroids were administered in 68.4% of patients, with a response rate of 92.3%; 1 patient required infliximab. One colitis-related death occurred. In univariable analysis, autoimmune disease, CTLA-4 inhibitor exposure, combination immunotherapy, and concurrent targeted therapy were significantly associated with colitis. In multivariable analysis, autoimmune disease (OR=6.10, 95% CI: 1.55-24.08; P=0.010), combination immunotherapy (OR=3.56, 95% CI: 1.09-11.63; P=0.035), and concurrent targeted therapy (OR=3.88, 95% CI: 1.31-11.54; P=0.015) remained independent predictors. ICI-induced colitis is an uncommon but clinically meaningful toxicity, and recognizing patients at higher risk may help guide closer monitoring and improve clinical management.