Gastric cancer is a leading cause of cancer-related death and approximately 60% of cases are diagnosed in Asia. The standard treatment is surgery and, particularly, in East Asia, gastrectomy with D2 nodal dissection (D2 gastrectomy). However, a considerable proportion of the patients relapse, and although different regimes of chemotherapy have been studied in an attempt to prevent recurrence, no regimen for adjuvant chemotherapy has been established in East Asia.

Mitsuru Sasako and collaborators were determined to find an effective adjuvant regimen: "when we started this study, there was no standard adjuvant chemotherapy in the world. Only the INT0116 study had showed a statistical significant effect of adjuvant treatment. Due to much worse overall results of this study and to worse local control by D0/1 [than by D2] dissection, Japanese investigators were not interested in it" explains Sasako. These investigators have now confirmed the rather striking results from the ACTS-GC study, which were originally published in 2007. In this 5-year follow-up phase III study, 1,034 patients with stage II or III gastric carcinoma who had undergone D2 gastrectomy were assigned to receive, or not, the oral fluoropyrimidine S-1 in 4-week cycles for 1 year. The 5-year overall survival rate was 71.7% in the S-1 group and 61.1% in the surgery-only group. Grade 3 or 4 adverse events occurred in less than 5% of the patients in the S-1 group. Whether these results can be extrapolated to countries outside East Asia has to be investigated, as some difference in the pharmacokinetics of the drug may exist among populations.

Another important result from this study is the high overall survival in patients in the surgery-only group (61.1%) compared with the overall survival rate in the surgery-only group in similar Western studies (28% in the INT0116 study and 23% in the MAGIC study). Clearly the quality of surgery is important, as Sasako explains: “we are still convinced that effective chemotherapy only is sufficient after high quality D2 dissection”.