A case of Stage IV gastric cancer with liver and peritoneal metastases responding completely to tailored S-1/CPT- 11 combination therapy

A 75-year-old man with advanced gastric cancer underwent distal gastrectomy with lymph node dissection(D1)and Roux-en Y reconstruction. Pathological staging was Stage IV (T3N3P1CY1M1), and curability was Cur C. He started adjuvant chemotherapy with oral administration of S-1(100 mg/body weight), but experienced grade 3 anorexia for one month. Abdominal computed tomography(CT)2 months postoperatively showed multiple liver metastases and ascites. We then conducted tailored S-1/CPT-11 as second-line chemotherapy(S-1 80 mg/body weight on days 1-5 and 8-12, CPT-11 60 mg/body weight on days 1 and 8). After 5 courses of this therapy, CT showed that the liver metastases and ascites had disappeared, leading to a complete response(CR). The only adverse event was general grade 1 fatigue. He continues to undergo oral administration of S-1(80 mg/body weight)as maintenance therapy, and maintained CR for 12 months since undergoing chemotherapy. Adverse events in tailored S-1/CPT-11 combination therapy are mild and tolerable, making this regimen a potential therapeutic strategy for patients with advanced or recurrent gastric cancer.