[A Case of Pathological Complete Response after Nivolumab Therapy in Unresectable Advanced Gastric Cancer].

A 70-year-old man was admitted to a local hospital with epigastric pain and diagnosed with type-2 gastric cancer. Contrast-enhanced CT scan showed metastases in S3 and S8 of the liver, and the tumor was classified as type cT4aN2H1, cStage ⅣB. Nivolumab monotherapy was initiated after failure of treatment with S-1 plus oxaliplatin and ramucirumab. After 6 courses, the primary tumor, lymph nodes, and liver metastases had shrunk to a remarkable degree. The patient underwent a proximal gastrectomy with D2 lymph node dissection and partial liver resection. Histopathological examination revealed no remaining tumor cells, with a histological response Grade 3.