Nivolumab-Induced Colitis in a Patient With Esophageal Adenocarcinoma: A Case Report.

Nivolumab is an immune checkpoint inhibitor used in the treatment of several types of cancer. Among the adverse effects of this drug, immune-mediated colitis (IMC) has been described. However, in contrast to other checkpoint inhibitors, such as ipilimumab, drug-induced colitis due to nivolumab is not commonly reported. We report the case of a 59-year-old male who had undergone surgical resection for gastroesophageal junction adenocarcinoma, had been on nivolumab during the past five months, and presented with worsening diarrhea. Colonoscopy demonstrated local edema and mild colitis in a region of the colonic mucosa located 30 cm distal to the ileocecal valve. Biopsies revealed acute moderate colitis. The patient responded well to loperamide and dietary modifications. Although nivolumab rarely causes IMC, this occurrence requires proper management in order to avoid further complications.