Stage IB-IIA Adenocarcinoma of the Stomach or Gastroesophageal Junction

This study is a randomized, controlled, open-label, multicenter trial. Patients who underwent radical resection for stage IB-IIA gastric or gastroesophageal junction adenocarcinoma were enrolled and stratified into low-risk and high-risk groups based on the presence of lymph node metastasis, vascular invasion, or elevated preoperative tumor markers (CEA or CA19-9). Patients in the low-risk group were directly enrolled in follow-up observation, while those in the high-risk group were randomized 1:1 to either close follow-up or adjuvant chemotherapy. The primary endpoint of the study is the efficacy and safety of adjuvant chemotherapy following radical resection in patients with stage IB-IIA gastric or gastroesophageal junction adenocarcinoma.