Gastrectomy with D2 lymphadenectomy plus postoperative chemotherapy is the standard treatment for resectable locally advanced gastric cancer in Japan. However, the prognosis of patients with serosa-positive tumors remains unsatisfactory because of peritoneal recurrence. This study aimed to investigate the validity of neoadjuvant therapy with docetaxel, cisplatin, and S-1 (DCS) in patients with locally advanced gastric cancer. Thirty patients with locally advanced gastric cancer underwent neoadjuvant DCS therapy at Dokkyo Medical University Hospital between June 2013 and October 2015. Gastrectomy and D2 lymphadenectomy were performed after two cycles of preoperative DCS therapy. The clinical responses of the primary gastric tumors based on endoscopic findings were partial response in 17 patients (57%) and stable disease in 13 patients (43%). Analysis of pathological response in the primary gastric lesions showed grade 1a in five patients (17%), grade 1b in nine patients (30%), grade 2 in 11 patients (37%), and grade 3 in five patients (17%). Twenty-four patients (80%) remained alive after a median follow-up period of 31 months. The 2- and 3-year overall survival rates in all patients were 89 and 70%, respectively. The 2-year overall survival rate in pathological responders (grade 1b-3) was 96%, compared with 50% in pathological non-responders (grade 1a) (P = 0.00187). Pathological responders had a significantly higher survival rate than non-responders. These results indicate that neoadjuvant DCS therapy may improve the prognosis in patients with serosa-positive locally advanced gastric cancer.
