[A Case of Complete Response to Trastuzumab plus S-1 and Oxaliplatin for a HER2-Positive Recurrence of Gastric Cancer].

The patient was an 84-year-old male who underwent a total gastrectomy for advanced gastric carcinoma. He received S-1 chemotherapy, but his serum tumor marker(CEA, CA19-9)level increased 6 months post operation. Computed tomography suggested lymph node swelling ofthe portcaval space(No.12p), and we treated him with chemotherapy that consisted of4 courses of Tmab plus SOX(trastuzumab plus S-1 plus oxaliplatin). The abdominal CT scan that was performed after 3 courses ofchemotherapy and PET-CT that was performed after 4 courses of chemotherapy suggested that the metastatic lesion had disappeared. We therefore assumed that a complete response had been achieved by Tmab plus SOX chemotherapy. A combination ofS -1 and cisplatin(SP)has been the standard regimen for advanced gastric cancer, but the combination ofS -1 plus oxaliplatin was demonstrated to be non-inferior to SP. We report this case with a review of the literature, because the patient with HER2-positive recurrent gastric cancer achieved a complete response after Tmab plus SOX chemotherapy.