Randomized phase II study designed to evaluate the efficacy and safety of continuous S-1 plus oxaliplatin versus intermittent S-1 plus oxaliplatin as first-line therapy in patients with recurrent and/or metastastic gastric carcinoma. Within 2 weeks of the end of induction chemotherapy of 6 cycles with S-1 plus oxalipatin, patients who don't experience progression will be randomized to the continuous S-1 plus oxaliplatin arm or the intermittent S-1 plus oxaliplatin arm in a 1:1 ratio.