Purpose: In our department, S-1 has been administered for 1 year as postoperative adjuvant chemotherapy for advanced gastric cancer since 2000. It was started by a standard dosage of 4-week administration with 2 weeks rest since 2000(A group). However, since 2002, it was changed with the expectation of the reduction of side effects by 2-week administration with a one-week rest(B group). Treatment continuity, adverse events and efficacy in both A and B groups were examined.
Subjects: The subjects were 96 patients with fStage II, III A and III B who were treated with S-1 after curative operation between 2000 and 2006.
Results: The percentage of patients who complied with the dosing instructions completely during a 1-year period was 70.2% in the A group and 77.6% in the B group. The incidence of Grade 3 and 4 toxicity was 1 nausea, 2 appetite loss, 1 neutropenia, 1 liver dysfunction in the A group and 1 nausea, 3 neutropenia in the B group, against, 76.6% in the A group and 44.9% in the B group, respectively, in the case of discontinuation, Thus, the trend in significantly high incidence in the A group was recognized. The 3-year survival rates in cases with a case of over 3 years were 88.5% in the A group and 87.5% in the B group, i. e., no difference.
Conclusion: Though the difference was not recognized in continuation rate, efficacy and adverse events in both A and B groups, there were significantly few withdrawal cases in the B group, and it seemed to be an effective medication method.