Pilot study of S-1 in patients with disseminated gastric cancer.

The prognosis for patients with advanced gastric cancer remains poor. Peritoneal metastasis is the most frequent cause of death in patients with gastric cancer, but the most appropriate treatment for patients with disseminated gastric cancer remains uncertain. S-1 is a newly developed oral fluoropyrimidine derivative with unusually high activity against several tumor types. The aim of this study was to evaluate the feasibility and efficacy of S-1 for the treatment of patients with disseminated gastric cancer. A total of 31 patients with primary or recurrent gastric cancer with peritoneal dissemination were entered into this study. One course of this single-drug therapy consisted of S-1 (80-120 mg) twice daily for 28 days, followed by a 2-week period of no treatment. These treatments were repeated until disease progression or patient refusal. With a median follow-up period in survivors of 293 days, the median survival time was 357 days. Toxicities were mild and no patient withdrew from treatment before disease progression. Grade 3 hematotoxicity was observed in only one patient. S-1 showed promising activity against gastric cancer with peritoneal dissemination and acceptable toxicity. Further evaluation of S-1 treatment is warranted in this disease.