Abstract: Objective To analyze cases of colitis induced by immune checkpoint inhibitors (ICIs) reported in literature in order to provide a reference for the clinical identification, diagnosis and management of such immune-related adverse events. Methods Databases including CNKI, VIP, Wanfang, PubMed, Web of Science, Embase and Cochrane Library were searched for related articles published as of June 2025. Reports of colitis caused by ICIs were screened, and patients’ demographics, tumor type, treatment regimens, onset time, severity, therapeutic strategies and outcomes were analyzed statistically. Results Ninety-eight articles involving 148 patients were included. The majority of the patients were male (72.97%), and the median age was 60. Lung cancer (41.21%) and melanoma (30.41%) were the most common primary tumors. PD-1 inhibitors were used in 81.76 % of the regimens. The median onset time from initiation of ICIs was 20.50 days. Severe colitis (grade 3-4) occurred in 72.97% of the cases. Corticosteroids were the major regimens (58.78%), and infliximab used in 14.86% of the cases. Most of the patients improved (69.59%), but 6.08% died. Conclusion Once severe colitis occurs after the use of ICIs, clinicians need to be alert for the possibility of immune-mediated colitis, especially diarrhea. A combination of glucocorticoid pulse therapy can yield good results.

Key words: Immune Checkpoint Inhibitors, Immunotherapy, Colitis, Immune-Related Adverse Events, Adverse Drug Reaction, Lung Cancer, Melanoma, Tumor