[Adjuvant chemotherapy using S-1 for curatively resected gastric cancer-the nationwide clinical trial].

Actually there has been no established adjuvant therapy for curable gastric cancer. Thus it is strongly recommended in the guidelines to actively carry out clinical trials. A large scale clinical trial on adjuvant chemotherapy for gastric cancer using S-1 (ACTS-GC) started in 2001. This was the first large trial having the surgery alone as control after 1980. The target population was Stage II, IIIA, IIIB, and the expected hazard ratio was less than 0.70. Between October 2001 and December 2004, for 3 years and 2 months, 1,056 patients were enrolled. Thus it was proven that we should carry out a pivotal study instead of making meta-analysis in the field of gastric cancer. Certainly, the results of this trial will strongly affect the clinical practice in Japan. If the results are negative, the use of adjuvant chemotherapy in practice and in social insurance might be restricted.