Objective:To investigate the clinical efficacy of neoadjuvant chemotherapy for the resectable locally advanced adenocarcinoma at the gastroesophageal junction.Methods:A retrospective cohort study was conducted to analyze 86 patients with resectable locally advanced Siewert type Ⅱ and Ⅲ adenocarcinoma at the gastroesophageal junction (T 3-4N +M 0) who were admitted to the Panzhihua Central Hospital of Sichuan Province from January 2013 to January 2016. All the patients were divided into the neoadjuvant chemotherapy group [preoperative XELOX regimen (oxaliplatin + capecitabine) adjuvant chemotherapy + surgery + postoperative XELOX regimen adjuvant chemotherapy, 46 cases] and non-neoadjuvant chemotherapy group (surgery + postoperative XELOX regimen adjuvant chemotherapy, 40 cases) according to whether neoadjuvant chemotherapy was performed before surgery. The total gastrectomy + Roux-en-Y esophagojejunostomy + D 2 lymphadenectomy or proximal subtotal gastrectomy + esophageal gastric remnant anastomosis + D 2 lymphadenectomy were applied to patients by the same team of doctors. The observation indicators included treatment situations, results of postoperative pathological examination and prognosis in the two groups. Results:In the neoadjuvant chemotherapy group, 25 patients (54.3%) had partial remission (PR), 21 patients (45.7%) had stable disease (SD), the clinical response rate was 54.3% (25/46), tumor control rate was 100.0% (46/46), and clinical stage reduction rate was 37.0% (17/46). Compared with the non-neoadjuvant chemotherapy group, the neoadjuvant chemotherapy group had a higher R 0 resection rate [100.0% (46/46) vs. 80.0% (32/40), χ2 = 4.024, P = 0.045], and in the neoadjuvant chemotherapy group, the pathological complete remission [tumor regression grade (TRG) 0] rate was 13.0% (6/46), and the overall pathological response (TRG 1 + TRG 0) rate was 56.5% (26/46). The postoperative pathological examination showed that the neoadjuvant chemotherapy group and the non-neoadjuvant chemotherapy group had statistically significant differences in the longest tumor diameter, vessel carcinoma embolus, perineural invasion, and pathological TNM staging (all P < 0.05). However, there was no statistical difference in the total humber of lymph nodes, the number of positive lymph nodes, pathological T stage, N stage, and human epidermal growth factor receptor 2 (HER2) expression in specimens (all P > 0.05). In the neoadjuvant chemotherapy group, 6 patients had grade 3 adverse reactions, and chemotherapy was suspended or the dose was adjusted. Adverse reactions in the blood system included the red blood cells reduction, white blood cells reduction and thrombocytopenia. Other adverse reactions included nausea, vomiting, and decreased appetite. There were no deaths related to radiotherapy. In the neoadjuvant chemotherapy group, the median tumor-free survival time was 20 months (5-36 months), and the 1-year and 3-year tumor-free survival rates were 89.5% and 52.4%, respectively; the median postoperative overall survival time was 20 months (9-36 months), and the 1-year and 3-year overall survival rates were 91.0% and 48.0%, respectively; 12 patients had tumor recurrence. In the non-neoadjuvant chemotherapy group, the median tumor-free survival time was 19 months (10-35 months), and the 1-year and 3-year tumor-free survival rates were 87.3% and 30.0%, respectively. The median postoperative overall survival time was 20 months (10-35 months), the 1-year and 3-year overall survival rates were 87.0% and 18.6%, respectively; 14 patients had tumor recurrence. There was a statistical difference in the tumor-free survival between the two groups ( χ2 = 4.522, P = 0.03), and there was no statistical difference in the overall survival between the two groups ( χ2 = 3.717, P > 0.05). Conclusions:XELOX regimen neoadjuvant chemotherapy is safe and effective for patients with resectable locally advanced Siewert type Ⅱ and Ⅲ adenocarcinoma at the gastroesophageal junction. It can decrease the tumor clinical stage and increase the R 0 resection rate and tumor-free survival rate.