A case of successful conversion surgery for gastric cancer with direct invasion to pancreatic head.

We experienced the case of successful conversion to distal gastrectomy for gastric cancer with direct invasion to the pancreatic head after the pre-operative chemotherapy. Esophagogastroduodenoscopy in a 66-year-old man revealed a tumor at the gastric antrum. Abdominal computed tomography (CT) showed that the tumor of the antrum was in contact with the pancreatic head. A biopsy of the tumor confirmed an adenocarcinoma and an overexpression of HER2 (3+). Staging laparoscopy showed the direct invasion of the gastric tumor to the pancreatic head. The patient received S-1, oxaliplatin and trastuzumab. After the pre-operative chemotherapy, CT showed a significantly shrinking tumor detached from the pancreatic head. Subsequently, distal gastrectomy was performed. Intra-operative exploration showed that the gastric tumor separated from the pancreatic head. The accumulation of trials for pre-operative chemotherapy for local advanced gastric cancer is expected.