A clinical results of TS-1 in advanced and recurrent gastric cancer in our hospital

A total of 40 patients with advanced and recurrent gastric cancer in our hospital were treated with TS-1 alone, and the efficacy of treatment, survival time, and adverse effects were examined. TS-1 was administered with the usual dosage and dose regimen. Response to treatment included a complete response (CR) in 3 cases, partial response (PR) in 8 cases, no change (NC) in 10 cases, and progressive disease (PD) in 7 cases. The response rate was 39.3%, and among the 28 patients with evaluable lesions TS-1 produced a high response rate of 56.3% in 16 patients who had undergone prior therapy. The median survival time (MST) was 478 days in the 28 patients with evaluable lesions, excluding patients with peritoneal dissemination, and 283 days in the 12 patients with peritoneal dissemination. The outcome was markedly poorer in the patients with peritoneal dissemination than in the patients with evaluable lesions. The incidence of grade 3 or higher adverse effects was 20%, including two cases in which decreased dihydropyrimidine dehydrogenase (DPD) activity was suspected, and one case in which decreased dihydropyrimidinase (DHP) was suspected. Although the effect of TS-1 alone on gastric cancer is significantly superior to that of any conventional cancer drugs, the results of this study suggest that the antitumor effect varies with the site of the target lesions and according to whether the lesion is a remnant or recurrence.