Immune Checkpoint Inhibitor-Induced Colitis Successfully Followed up by Ultrasonography

Characteristics and usefulness of transabdominal ultrasonography in immune-mediated colitis

BACKGROUND/AIMS

The usefulness of ultrasonography (US) in diseases of the gastrointestinal tract has been reported recently. This prospective study aimed to determine the features of US findings in immune-mediated colitis (IMC), an adverse event induced by immune checkpoint inhibitor, and examine the correlation between US findings, colonoscopy (CS) findings, and severity of colitis.

METHODS

We studied patients examined using CS and US upon suspicion of IMC in Hokkaido University Hospital between April 2018 and February 2021. Endoscopic findings of IMC were assessed using the Ulcerative Colitis Endoscopic Index of Severity (UCEIS). The severity of US findings in IMC was evaluated using US grade, which is the ultrasonographic grading scale in ulcerative colitis. Bowel wall thickness and the intensity of the color Doppler signal were also analyzed. Severity of colitis was evaluated using Common Terminology Criteria for Adverse Events (CTCAE) grade version 5.

RESULTS

Fourteen patients with IMC were enrolled. The US findings were bowel wall thickening, loss of stratification, ulceration and increased blood flow signal. The US grade was moderately correlated with the UCEIS (r=0.687, p=0.009) and CTCAE grade (r=0.628, p=0.035). Bowel wall thickness and UCEIS (r=0.628, p=0.020), as well as color Doppler signal grade and CTCAE grade (r=0.724, p=0.008), were significantly correlated.

CONCLUSIONS

US findings in IMC were mainly similar to those of ulcerative colitis, but there were some findings that were characteristic only of IMC. Significant correlation was found between US findings, CS findings, and severity of colitis. Hence, US could be useful for the evaluation of IMC.

A case of immune checkpoint inhibitor-associated gastroenteritis detected by ultrasonography

While immune checkpoint inhibitors (ICIs) have antitumor effects, they also have characteristic side effects, including colitis. However, gastritis has rarely been reported. We report a case of a patient with lung adenocarcinoma who presented with epigastric pain and diarrhea following pembrolizumab administration. Sonography of the abdomen demonstrated diffuse, although mild, gastric wall thickening (mainly in the submucosa), as well as a slight decrease in echogenicity throughout the gastric wall. While the mucosal surface was relatively smooth, color Doppler examination showed increased vascularity. Esophagogastroduodenoscopy and pathological examination confirmed the diagnosis of ICI-related gastroenteritis.