Yoshikawa T, et al. - For patients with stage II gastric cancer, researchers examined the non-inferiority of four courses of S-1 vs eight courses of S-1. They conducted a phase 3, open-label, randomized controlled, non-inferiority trial at 59 hospitals in Japan. For this trial, patients (aged 20–80 years) with stage II adenocarcinoma of the stomach were randomly assigned (1:1) to eight courses or four courses of S-1. Ultimately, 590 patients were enrolled between February 16, 2012 and March 19, 2017. In May 2017, the updated 3-year relapse-free survival rate was 93.1% for the eight-course group and 89.8% for the four-course group. For stage II gastric cancer, S-1 for 1 year should remain as standard adjuvant chemotherapy. Neutropenia was the most common grade 3–4 adverse event.