 Method: This study, which started from January, 2011 and planned to close after ten years, has been approved by the ethic committee of Sun Yat-sen University, with written inform consent obtained from all enrolled subjects. Patients who had histologically proven gastric adenocarcinoma and confirmed lymph node metastasis to para-aortic nodes 3 enlarged lymph nodes were prospectively enrolled in this trial. A standard D2 lymphadenectomy or D4 procedure was randomly decided by a formal randomization program. The primary end point of this study was overall survival, defined as the time from randomization to death. The secondary end points were recurrence-free survival, postoperative complications, length of stay, and hospital charges. Recurrence-free survival was defined as the time from randomization to the first recurrence of cancer or death from any cause. The follow-up period would last for at least five years after the definitive operation. 