Oxaliplatin Combined With S-1(SOX) Neoadjuvant Chemotherapy for Different Cycles in Patients With Gastric Cancer

The preoperative SOX chemotherapy consists of three-week cycles of intravenously administered oxaliplatin 130 mg/m2 on day 1 and orally administered S-1 40-60 mg twice a day (BID) on day 1 to 14. The dose of S-1 depends on body surface area (BSA): 40mg BID for BSA \< 1.25 m2; 50mg BID for 1.25 m2 \< BSA \<1.5 m2; 60mg BID for BSA \> 1.5 m2. Day 15 to day 21 is the rest period.

Surgery is planned 3-4 weeks after the last cycle of chemotherapy. A standard D2 radical laparoscopic gastrectomy is recommended. The extent of gastric resection and lymphadenectomy were performed as per the treatment guidelines. Reconstruction after gastrectomy was decided by the surgeon. All operations are performed by well trained and experienced surgical team to guarantee the quality of surgery, including harvesting more than 16 lymph nodes.

Laparoscopic exploration is to detect occult peritoneal metastases and inspect the primary lesion, liver, diaphragm, pelvic organs, bowel and omentum according to the standard acquirements reported before. Patients with any patterns of distant metastases, suggestive of distant metastasis (M1), will be excluded from the trial.