Efficacy and feasibility of combination chemotherapy with S-1 and cisplatin (2 weeks regimen) for advanced gastric cancer.

Objective: Although combination chemotherapy with 3 weeks of S-1 and cisplatin is effective for advanced gastric cancer, the toxicities of S-1 which mostly occur during the third week of administration are a major problem. To achieve fewer adverse effects with S-1 and higher dose intensity of cisplatin, we performed combination chemotherapy with 2 weeks of S-1 and cisplatin as first line. The aim of this retrospective study was to analyse the efficacy and feasibility of this regimen.

Methods: S-1 (40-60 mg depending on patient's body surface area) was given orally twice daily for 2 consecutive weeks, and 70 mg/m(2) cisplatin was given intravenously on day 8, followed by a 2-week rest period.

Results: Forty-eight patients received a total of 184 courses of chemotherapy. Overall response rate was 40.6% and median survival time was 411 days. Dose intensities were 257.6 mg/m(2)/week for S-1 and 16.4 mg/m(2)/week for cisplatin. The incidences of grade 3/4 haematological toxicities were leucopenia (19%), neutropenia (29%) and anaemia (17%), and those of grade 3 non-haematological toxicities were anorexia (31%) and nausea (21%). The rate of treatment discontinuation owing to toxicity was 10%.

Conclusions: This regimen may be effective as an alternative therapy to 3 weeks of S-1 and cisplatin to reduce the toxicity of chemotherapy for advanced gastric cancer.