Pancreaticoduodenectomy after neoadjuvant chemotherapy for gastric cancer invading the pancreatic head: A case report.

BACKGROUND: Pancreaticoduodenectomy (PD) for advanced gastric cancer is rarely performed because of the high morbidity and mortality rates and low survival rate. However, neoadjuvant chemotherapy for advanced gastric cancer has improved, and chemotherapy combined with trastuzumab may have a preoperative tumor-reducing effect, especially for human epidermal growth factor receptor 2 (HER2)-positive cases. CASE SUMMARY: We report a case of successful radical resection with PD after neoadjuvant S-1 plus oxaliplatin (SOX) and trastuzumab in a patient (66-year-old male) with advanced gastric cancer invading the pancreatic head. Initial esophagogastroduodenoscopy detected a type 3 advanced lesion located on the lower part of the stomach obstructing the pyloric ring. Computed tomography detected lymph node metastasis and tumor invasion to the pancreatic head without distant metastasis. Pathological findings revealed adenocarcinoma and HER2 positivity (immunohistochemical score of 3 +). We performed staging laparoscopy and confirmed no liver metastasis, no dissemination, negative lavage cytological findings, and immobility of the distal side of the stomach due to invasion to the pancreas. Laparoscopic gastrojejunostomy was performed at that time. One course of SOX and three courses of SOX plus trastuzumab were administered. Preoperative computed tomography showed partial response; therefore, PD was performed after neoadjuvant chemotherapy, and pathological radical resection was achieved. CONCLUSION: We suggest that radical resection with PD after neoadjuvant chemotherapy plus trastuzumab is an option for locally advanced HER2-positive gastric cancer invading the pancreatic head in the absence of non-curative factors.