[A Case of Type 4 Gastric Cancer with Esophageal Invasion That Responded to Neoadjuvant Chemotherapy Containing S-1 and Oxaliplatin followed by Surgery].

We encountered a case of type 4 gastric cancer with esophageal invasion that responded to neoadjuvant chemotherapy containing S-1 and oxaliplatin(SOX)followed by surgery, which could be curative resection. A 46-year-old man was referred to our hospital because of abnormal upper gastrointestinal series findings. He was diagnosed with type 4 advanced gastric cancer with esophageal invasion, cT4b(diaphragm)N2M0, Stage ⅢC, and 3 courses of neoadjuvant SOX therapy were administered. Adverse events were minor. After NAC, the primary lesion and lymph nodes showed marked reductions on CT; total gastrectomy and subtotal thoracic esophagectomy were performed. The pathological response to NAC was evaluated as Grade 2 in the primary tumor and Grade 3 in the lymph node; overall, NAC showed considerable antitumor effects. The final diagnosis was ypT3N0M0P0CY0H0, StageⅡA, and was judged as curatively resected. Currently, we are continuing to administer adjuvant chemotherapy containing S-1.