[A case of gastric cancer in which grade 2 treatment effects were obtained with preoperative two-week S-1 administration].

In our hospital, a clinical trial on the effects of preoperative 2-week S-1 administration for advanced gastric cancer is being conducted. A7 5-year-old man presented to our hospital with a type 2 tumor(poorly differentiated adenocarcinoma)in the pyloric antrum. Subpyloric lymph node enlargement and a c-T2(MP), N1, M0, Stage II A tumor (according to the gastric cancer handling agreement, 14th edition)were diagnosed, and S-1(100mg/day)was subsequently administered for 14 days. On day 15, we performed laparoscopy-assisted distal gastrectomy, with D2 dissection. Analysis of the resected specimen, ie the primary tumor and metastatic lymph nodes, confirmed the effect of the treatment as Grade 2, and revealed a type 2 gastric cancer of 30×20mm in size; this tumor was downstaged to yp-T1b(SM), N1, Stage I B. No adverse events associated with perioperative S-1 were observed, and the postoperative course was good. At the latest follow-up(6 years after treatment), no recurrence was observed.