[Complete histological response in gastric cancer stage IV after neoadjuvant chemotherapy including S-1 combined with CDDP--report of a case].

A 60-year-old man complaining of black stool, body weight loss, and anemia, was examined and diagnosed with advanced gastric cancer (M, type 3, por 2, cT3, cN3, cH0, cP0, cM0, cStage IV). A poor prognosis was predicted, yet we tried neoadjuvant chemotherapy (NAC) expecting downstaging of the tumor. Considering the efficacy and safety, we chose S-1+CDDP as the NAC regimen. S-1 (120 mg/day) was administered orally for 21 days, followed by CDDP (75 mg/body) div on day 8. Distal partial gastrectomy and lymph node dissection (D2) were performed, with Billroth I reconstruction. Histological examination of the resected stomach and lymph nodes revealed no residual cancer cells, suggesting complete histological remission (grade 3) according to the Japanese classification of gastric carcinoma.