Abstract
【Background & Aim】Immune checkpoint inhibitors（ICI）may cause immune-related adverse events（irAE）, especially diarrhea and colitis. We retrospectively investigated diarrhea and colitis caused by ICI in our hospital.【Subjects & Methods】Ninety-eight patients who ICI were newly administered at our hospital from July 1, 2014 to June 30, 2019 were retrospectively analyzed. The primary endpoint is the frequency of onset of ICI related diarrhea/colitis. Furthermore its clinical characteristics were considered and a clinical comparison with unaffected cases was performed.【Results】 The frequency of onset of ICI related diarrhea/colitis was 9.2％ in nine cases, CTCAE Grade 1 in seven cases in 77.8％, and Grade 2 in two cases in 22.2％. Compared with 89 cases without diarrhea/colitis, the number of ICI administration and response rate（CR + PR）were significantly higher in the cases of occurrence.【Summary】Although the frequency of onset of ICI related diarrhea / colitis in our hospital was at the same level as existing reports, it is necessary for each department to cooperate in dealing with irAE, which may increase in the future.
