[Two Cases of Complete Response to Trastuzumab Combined with Chemotherapy for Recurrence of HER2-Positive Gastric Cancer].

Case 1: A 67-year-old male underwent distal gastrectomy for advanced gastric cancer. Postoperative histopathological examination indicated pT2a, pN2, M0, pStage ⅢA. He received 4 courses of TS-1 with paclitaxel chemotherapy and TS-1 chemotherapy for 2 years. Three years and 5 months after surgery, computed tomography suggested lymph node metastasis of the mediastinum, so TS-1 with cisplatin(CDDP)therapy was administered. Five years and 10 months after surgery, recurrence occurred and docetaxel and CPT-11 were administered with no response. Since HER2 was overexpressed in the primary tumor, he was treated with capecitabine, CDDP, and trastuzumab(XPT)therapy. After 1 year and 6 months, the patient was considered to have achieved a complete response(CR), and after further trastuzumab therapy for half a year, CR was maintained for 12 years and 3 months after surgery. Case 2: A 59-year-old female underwent total gastrectomy for advanced gastric cancer. Postoperative histopathological examination indicated pT3, pN3a, M0, pStageⅢB. She received TS-1 chemotherapy for 1 year and 8 months. Computed tomography suggested paraaortic lymph node metastasis, and XPT therapy was administered. The patients responded well, and alternate administration of XPT and capecitabine and docetaxel(XT) was performed. Three years and 5 months after surgery, recurrence of lymphadenopathy occurred and intensity-modulated radiation therapy in addition to XPT/XT alternate therapy was introduced, leading to a CR 5 years and 8months after surgery. XT therapy was continued afterward, and CR was maintained for 9 years and 2 months after surgery.