A Randomized Phase 3 Clinical Trial Investigating Optimal Duration of Oxaliplatin Administration in Postoperative XELOX (Oxaliplatin + Capecitabine) Adjuvant Chemotherapy for the Patients With Stage II/III Gastric Cancer

XELOX (oxaliplatin + capecitabine) combination chemotherapy is considered a standard adjuvant treatment for curatively resected gastric cancer patients after it proved its effecacy in the CLASSIC trial. Adjuvant XELOX chemotherapy is a long-term treatment with a total treatment period of 6 months and it is known that about 33% of patients cannot complete treatment schedule due to side effects. In particular, peripheral neuropathy, which is caused by the cumulative administration of oxaliplatin, is a major cause of lowering the patient's quality of life and treatment compliance, and it is known that the incidence rate increases when standard XELOX treatment is continued for more than 6 cycles. In colorectal cancer, clinical studies have been actively conducted to shorten the duration of standard adjuvant chemotherapy to reduce the peripheral sensory neuropathy caused by oxaliplatin, but there are no relevant studies in gastric cancer. This study aims to compare the efficacy and safety of reduced adjuvant XELOX treatment (4 cycles of XELOX followed by 4 cycles of capecitabine alone) to standard adjuvant XELOX treatment (8 cycles of XELOX).