Real-World Management and Outcomes of Immune-Mediated Diarrhea and Colitis: Gaps in Guideline Adherence and Opportunities for Implementation

Purpose Immune-mediated diarrhea and colitis (IMDC) is a high-risk toxicity frequently experienced by patients treated with immune checkpoint inhibitors (ICIs) and requiring rapid supportive care interventions. Delays in IMDC reporting and inconsistent guideline adherence increase symptom burden and emergency department (ED) utilization. Although current practice guidelines provide IMDC management recommendations, adherence in routine oncology care remains uncertain. This study evaluated IMDC management and guideline concordance at a single National Cancer Institute–designated comprehensive cancer center to identify workflow opportunities to improve supportive management. Methods We conducted a retrospective observational study of adults treated with ICIs between 2011 and 2024 who developed IMDC. Electronic health record (EHR) data were used to characterize patient demographics, IMDC reporting patterns, and to assess National Comprehensive Cancer Network (NCCN) guideline concordance in terms of IMDC diagnostic workup and management across care settings. Results ED clinicians demonstrated greater adherence to NCCN guidelines than outpatient oncology providers. Of the 17 patients with IMDC, nine (52.94%) required ED management, with an average immunosuppressive therapy duration of 92.29 days, and only four (23.53%) resumed ICI therapy following IMDC resolution. Despite 88.24% of patients presenting with moderate-severe IMDC, 41.18% experienced symptoms for over a week before seeking medical care. Over 40% of patients with IMDC experienced concurrent immune-related adverse events (irAEs), with dermatitis and hepatitis being the most common. Conclusion Our findings reveal actionable targets for improving IMDC supportive management. Implementing standardized workflows and decision-support tools may strengthen evidence-based IMDC care, reduce treatment delays, and improve patient outcomes.