[Conversion Surgery Performed after SOX plus Nivolumab Therapy for Advanced Gastric Cancer with Para-Aortic Lymph Node Metastasis].

The patient was a 78-year-old woman. She presented with anemia and a positive fecal occult blood test. Endoscopic findings revealed type 3 advanced gastric cancer. As it had metastasized to the para-aortic lymph node(PALN: No. 16a2 lat), it was diagnosed as gastric cancer at cardia cT4aN1(No.1)M1(No.16a2 lat), cStage Ⅳ. She was administered S-1, oxaliplatin, and nivolumab(SOX plus Nivo)therapy as a first-line treatment. SOX plus Nivo resulted in a remarkable reduction of the lymph nodes, which were PR. After 3 courses of chemotherapy, a laparoscopic proximal gastrectomy was performed, with D2 plus No. 16a2 int/lat lymph nodes dissection as conversion surgery. Histopathological examination was pT3N0M0, and R0 resection was pStage ⅡA. She was discharged at POD21 and started S-1 from POD69. The patient is alive with no signs of recurrence 10 months postoperatively.