A Case of Advanced Gastric Cancer with Severe Lymph Node Metastasis in which Complete Clinical Response was Achieved by the Immune Checkpoint Inhibitor Nivolumab

Abstract

An 86-year-old man presented with epigastric discomfort and was diagnosed with type 3 gastric cancer located at the lesser curvature of the middle stomach by an upper gastrointestinal endoscopy elsewhere. After various examinations in our hospital, the cancer was determined to be cT3N2M0 cStage III and surgery was recommended. Intraoperative findings showed enlarged hepatic hilar lymph nodes, common hepatic artery lymph nodes, and left gastric artery lymph nodes which were piled one upon another. A radical resection was abandoned and only gastrectomy was performed. TS-1 administration was started postoperatively, but an abdominal computed tomography (CT) scan 10 months after the surgery showed enlarged metastatic lymph nodes. Hence, the patient was switched to paclitaxel plus ramucirumab treatment, however, the lymph nodes did not shrink, and nivolumab was started 19 months after the surgery. Although there was no lymph nodes enlargement seen on CT scan 22 months after the surgery, there was evidence of nivolumab-induced hypopituitarism. Administration of nivolumab was thus discontinued. As of 40 months after the surgery, the patient is alive without recurrence of the disease. The response rate of nivolumab in metastatic gastric cancer is reported to be about 11%, and complete response is extremely rare. Here we report a case of complete response of unresectable gastric cancer to nivolumab.