[A Long-Term Survival Case of HER2-Positive Gastric Cancer with Distant Lymph Node Metastasis Receiving Multidisciplinary Therapy].

An 82-year-old man presented with right cervical swelling. Cervical ultrasonography revealed several swollen lymph nodes which were diagnosed with adenocarcinoma by fine needle aspiration cytology. Computed tomography showed right axillary lymph nodes were also swelling. Upper and lower gastrointestinal endoscopy found type 0-Ⅱa gastric cancer located at the posterior wall of the middle region. Pathology was HER2-positive moderately differentiated tubular adenocarcinoma. Doublet chemotherapy with S-1 and cisplatin was administered for unresectable gastric cancer(cT1bN0M1, cStage Ⅳb). One month later, doublet chemotherapy was changed to triplet chemotherapy with trastuzumab, capecitabine, and cisplatin. A month later, complete response(CR)was achieved. After 8 courses of triplet chemotherapy, we changed to doublet chemotherapy with trastuzumab and capecitabine due to impaired kidney function 8 months. Two months later from that, endoscopic mucosal dissection was performed for gastric cancer as local therapy(pathology: well differentiated tubular adenocarcinoma, pT1a, ly0, v0). Two years and 2 months after the beginning of chemotherapy, the right axillary lymph nodes were enlarged again and surgically resected(pathology: HER2-positive poorly differentiated adenocarcinoma). He had CR for 8 years and 2 months, and chemotherapy was canceled due to his decision. During 1 year and 7 months, disease progression was not observed. We present a long-term survival case of HER2-positive gastric cancer with distant lymph node metastasis receiving multidisciplinary therapy.