Severe perioperative immune-related adverse events requiring intensive care in patients with gastric cancer: a case series

The treatment strategy for advanced gastric cancer is significantly changing with the development of immune checkpoint inhibitors. While the efficacy of immune checkpoint inhibitors has been demonstrated, immune-related adverse events can present a wide spectrum of symptoms, ranging from mild and non-specific to severe symptoms. In some cases, intensive care unit management is required. Despite the widespread application of immune checkpoint inhibitor therapy, perioperative immune-related adverse events remain under-reported and insufficiently discussed. Case 1 is a 46-year-old Japanese female underwent laparoscopic proximal gastrectomy after S-1, oxaliplatin plus nivolumab therapy for unresectable locally advanced esophagogastric junction cancer and developed diabetic ketoacidosis and fulminant type 1 diabetes mellitus 37 days after surgery. Case 2 is a 78-year-old Japanese male underwent staging laparoscopy after S-1, oxaliplatin plus nivolumab therapy for unresectable advanced gastric cancer and developed fulminant type 1 diabetes mellitus and bullous pemphigoid 13 days after surgery. Case 3 is a 64-year-old Japanese male underwent distal gastrectomy with D2 lymph node dissection and para-aortic lymph node sampling after S-1, oxaliplatin plus nivolumab therapy for unresectable advanced gastric cancer and developed clinically suspected immune-related encephalitis 2 days after surgery. All three patients required intensive care management with temporary ventilatory support. Appropriate treatment was performed, and all patients are alive and undergoing postoperative treatment. As immune checkpoint inhibitors are increasingly incorporated into multidisciplinary treatment for gastric cancer, surgeons may encounter severe perioperative immune-related adverse events requiring intensive care management. Awareness of these presentations and prompt multidisciplinary management may help facilitate early recognition and appropriate treatment.