Successful treatment of refractory immune checkpoint inhibitor-related colitis after ileostomy creation: case report and literature review

Abstract BackgroundImmune checkpoint inhibitors are widely used for treating malignant tumors, changed the framework of cancer treatment, but on the other hand, Immune-related adverse event occurs due to excessive immune response. Immune checkpoint inhibitor-related colitis shows symptoms similar to ulcerative colitis, and high-dose corticosteroids and anti-TNF-alpha antibodies are recommended, but surgical treatment has not yet been established for cases that are refractory to medical therapy.Case presentationThis case involved a 64-year-old male. PD-L1 expression in the recurrent lesion of lung adenocarcinoma was positive, and treatment with pembrolizumab was initiated. Hematochezia and diarrhea were observed 8 weeks after the start of the treatment and was diagnosed as irAE colitis. The patient was treated with corticosteroid, infliximab, mesalazine, and leukocytapheresis for irAE colitis, but was refractory. The patient's performance status was poor, and proctocolectomy and subtotal colectomy according to the treatment of refractory ulcerative colitis were not indicated, so a diverting loop ileostomy was performed to rest the colon. The abdominal symptoms resolved after the surgery, and chemotherapy was resumed 3 months after surgery. Stoma closure could not be performed because the mucosal lesions did not improve on colonoscopy; nevertheless, there were no symptoms of irAE colitis, and nivolumab could be administered from the eighteenth month after surgery. However, it was not effective, and the patient died of the primary disease two years after surgery.Discussion and ConclusionsWe encountered a case in which a diverting loop ileostomy was performed for irAE colitis refractory to medical treatment, and the symptoms were alleviated. However, surgical treatment of refractory irAE colitis and resumption of ICIs after irAE development need to be fully discussed.