Clinical, Endoscopic, and Pathological Characteristics of Immune Checkpoint Inhibitor-Induced Gastroenterocolitis

Excerpt

Recently, the advent of Immune checkpoint inhibitor (ICI) enables improvement of the prognosis in various malignant tumors. Programmed cell death protein 1 (PD-1) inhibitors, Programmed cell death protein 1 Ligand 1 (PD-L1) inhibitors, and Cytotoxic T lymphocyte antigen-4 (CTLA-4) have proven to be effective against malignant melanoma, non-small cell lung cancer, renal cell carcinoma, and gastric cancer [1‐3]. The side effects of ICI are generally referred to as immune-related adverse events (irAE), and irAE gastroenterocolitis is considered one of the important side effects. In fact, it has been reported that 27–54% of patients treated with anti-CTLA-4 inhibitors develop diarrhea, and 8–22% develop colitis [4]. Symptoms of irAE gastroenterocolitis including, diarrhea, abdominal pain, and bloody stool are known. Although the onset of irAE gastroenterocolitis is often recalled from the timing of drug administration and clinical symptoms, there are many similarities to IBD in terms of endoscopic and pathological findings, but there are no clear diagnostic criteria [5]. The aim of this report was to elucidate the clinical, endoscopic and pathological characteristics of ICI-induced gastroenterocolitis. …