[Evaluation of S-1 for stage IV gastric cancer]

To evaluate the efficacy of S-1 for Stage IV gastric cancer, we retrospectively examined 124 patients with Stage IV gastric cancer. We classified patients into two groups based on the presence or absence of S-1 administration: the S-1 therapy group (n= 56) and the non-S-1 therapy group (n=68). Basically, patients received S-1 orally at 40 mg per square meter of body surface area twice daily for 4 weeks, followed by 2 weeks without chemotherapy. When side effects appeared, we tried dose reduction or cut short the administering period according to the dose modification criteria. Major patient characteristics were as follows: gender (male/female: 76/48), and age (median[range]: 63[24-83]). The median S-1 dosage was about 5 courses, and the median of the S-1 total dosage was 10. 08 g, based on the amount of tegafur. The relative dose intensity (RDI) was well maintained (average: 74. 9%). The survival rate in the S-1 therapy group was significantly higher than in the non-S-1 therapy group. The median survival time (MST) was 308 days in the S-1 group and 157 days in the non-S-1 group. In the S-1 therapy group, the MST was 629 days for those receiving 10 g or more, while that of those receiving less than 10 g was 209 days. The MST of patients administered 10 g or more was significantly longer than that of those receiving less than 10 g (p<0. 0001). Therefore, we consider that S-1 therapy improves survival in patients with Stage IV gastric cancer.