Advanced gastric cancer can respond to S-1, an oral fluoropyrimidine.
Dr Shinichi Sakuramoto and colleagues tested S-1 as adjuvant chemotherapy in patients with curatively resected gastric cancer.
The research team identified patients in Japan with stage II or III gastric cancer who underwent gastrectomy with extended lymph-node dissection.
The patients were randomly assigned to undergo surgery followed by adjuvant therapy with S-1 or to undergo surgery only.
|The 3-year overall survival rate was 80% in the S-1 group|
|New England Journal of Medicine|
The team reported that in the S-1 group, administration of S-1 was started within 6 weeks after surgery and continued for 1 year.
The treatment regimen consisted of 6-week cycles in which, in principle, 80 mg of oral S-1 per square meter of body-surface area per day was given for 4 weeks.
No chemotherapy was given for the following 2 weeks.
The team's primary end point was overall survival.
The team randomly assigned 529 patients to the S-1 group, and 530 patients to the surgery-only group between 2001 and 2004.
The trial was stopped on the recommendation of the independent data and safety monitoring committee.
The first interim analysis, performed 1 year after enrollment was completed, showed that the S-1 group had a higher rate of overall survival than the surgery-only group.
Analysis of follow-up data showed that the 3-year overall survival rate was 80% in the S-1 group, and 70% in the surgery-only group.
The researchers found that the hazard ratio for death in the S-1 group, as compared with the surgery-only group, was 0.70.
The team observed that adverse events of grade 3 or grade 4 relatively common in the S-1 group were anorexia, nausea, and diarrhea.
Dr Sakuramoto's team concluded, "S-1 is an effective adjuvant treatment for East Asian patients who have undergone a D2 dissection for locally advanced gastric cancer."