Immune Checkpoint-Induced Colitis: A Single-Center Retrospective Cohort Study

Area of Science:

• Oncology
• Gastroenterology
• Immunology

Background:

• Immune checkpoint inhibitors (ICIs) revolutionized cancer treatment but can cause immune-related adverse events, notably colitis.
• Understanding and managing ICI-induced colitis is crucial due to the increasing use of these therapies.

Purpose of the Study:

• To detail the clinical, endoscopic, and histological characteristics of ICI-induced colitis.
• To assess treatment outcomes for ICI-induced colitis using corticosteroids and biologicals in a real-world setting.

Main Methods:

• A retrospective cohort study of 77 adult patients with ICI-induced colitis (2012-2023).
• Analysis of clinical, biochemical, endoscopic, histological data, and treatment response/safety outcomes.

Main Results:

• Microscopic colitis was found in 88% of patients with normal endoscopic findings.
• Combination ICI therapy correlated with higher Mayo scores and greater need for biologicals (p=0.011).
• Clinical response rates were 79.6% for corticosteroids and 100% for biologicals; ICI rechallenge had a 17.4% relapse rate.

Conclusions:

• Microscopic findings on random biopsies are common in ICI-induced colitis, even without endoscopic signs.
• Combination ICI therapy may indicate a need for early escalation to biologicals due to corticosteroid resistance.
• ICI rechallenge is feasible with manageable colitis morbidity, though prospective studies are warranted.