chemotherapy regimens using biochemical modulation and/or combination therapies have improved the prognosis of patients with gastric cancer. S-1 is an oral anticancer agent that was developed based on the theory of the biochemical modulation of 5-FU. S-1 is composed of tegafur (FT, a prodrug of 5-FU), 5-chloro-2,4-dihydroxypyridine (CDHP), and potassium oxonate (Oxo), at a molar ratio of 1 : 0.4 : 1 [1]. CDHP inhibits the biodegradation of 5-FU, and Oxo reduces 5-FUinduced gastrointestinal toxicities. In summary, S-1 not only increases the anticancer activity but also reduces the adverse reactions of 5-FU. In clinical studies, as a single agent, S-1 has demonstrated a higher response rate against gastric cancer compared to any other anticancer agent [2][3][4]. S-1 has become one of the drugs used in first-line chemotherapy for advanced or recurrent gastric cancer in Japan.In an attempt to increase the efficacy of S-1, several combination chemotherapy regimens using S-1 have been examined, and cisplatin (CDDP) has received attention as a result of its remarkable activity. Koizumi et al.[5] performed a phase I/II study of S-1 plus CDDP for patients with advanced gastric cancer. S-1 was administered at a standard dose for 3 weeks, and the recommended dose of CDDP, infused on day 8, was 60 mg/ m 2 ; this study revealed an overall response rate of 74%. Baba et al. [6] treated 12 patients using the same schedule, and showed a response rate of 66.7%. These results suggested the excellent therapeutic efficacy of the combination of S-1 and CDDP in the treatment of gastric cancer. However, the effect of the combination therapy on survival has been unclear.The aim of the present study was to evaluate the long-term outcome of combination therapy of CDDP and S-1. We compared, retrospectively, the clinical results of treatment with S-1 alone and treatment with S-1 plus CDDP in patients with advanced or recurrent gastric cancer who were treated in our hospital.
AbstractBackground. Although combination therapy of S-1 and cisplatin (CDDP) has excellent efficacy against gastric cancer, the effect of the treatment on survival has been unclear. The aim of this study was to evaluate the long-term outcome of this combination therapy. Methods. Sixty-three patients with advanced or recurrent gastric cancer were treated with S-1, with or without CDDP, as first-line chemotherapy, and the clinical results were compared retrospectively. S-1 was administered orally at a standard dose of 80 mg/m 2 . In the treatment of the S-1 group, S-1 was given for 28 consecutive days, followed by a 14-day rest. In the treatment of the S-1/CDDP group, S-1 was given for 21 consecutive days, followed by a 14-day rest, and CDDP, at 60 mg/m 2 , was infused on day 8. Results. The incidence of adverse reactions of more than grade 3 was 22.5% in the S-1 group and 43.5% in the S-1/ CDDP group, and the treatment compliance was better in the S-1 group. The overall response rate was 25.9% in the S-1 group, and 36.8% in the S-1/CDDP group. The combination of S-1 with...