Phase I/II Study of Neoadjuvant Chemoradiotherapy With S-1/ Oxaliplatin in Patients With Gastric Cancer: Randomized Phase II Study of S-1/RT vs. S-1/Oxaliplatin/RT

Inclusion Criteria: * Patients older than 18 years * Patients with localized, histologically confirmed gastric or gastroesophageal adenocarcinoma ③ Localized gastric cancer of clinical stage (T2N(+), T3/T4) * ECOG performance status of 0 to 1 ⑤ Adequate organ function as evidenced by the following; Absolute neutrophil count \> 1.5 x 109/L; platelets \> 100 x 109/L; total bilirubin ≤1.5 UNL; AST and/or ALT \< 5 UNL; creatinine clearance ≥ 50mL/min ⑥ Written informed consent form Exclusion Criteria: * T1 (regardless of N stage), T2N0 * M1 ③ Peritoneal seeding ④ Uncontrolled medical condition