Oncological outcomes of function-preserving gastrectomy for early gastric cancer: a multicenter propensity score matched cohort analysis comparing pylorus-preserving gastrectomy versus conventional distal gastrectomy

Objective: This study aimed to clarify the oncological safety of pylorus-preserving gastrectomy (PPG) compared with conventional distal gastrectomy (DG). Methods: From three institutions specializing in cancer, the medical records for a cohort of 2898 consecutive patients who had undergone DG (n = 2208) or PPG (n = 690) for clinical stage I gastric cancer between January 2006 and December 2012 were analyzed. A propensity score for each patient was estimated on the basis of 38 preoperative clinical and tumor-related factors. After propensity score matching had been done, 1004 patients (502 DG patients, 502 PPG patients) were included in the analysis. The overall survival, relapse-free survival, and occurrence of secondary gastric cancer were then compared. The median observation period was 48.6 months (range 1–109.8 months). Results: The 5-year overall survival rate was 98.4 % for the PPG group and 96.6 % for the DG group (hazard ratio 0.48, 95 % confidence interval 0.21–1.09, P = 0.07). The 3-year relapse-free survival rate was 99.5 % for the PPG group and 98.0 % for the DG group (hazard ratio 0.39, 95 % confidence interval 0.12–1.33, P = 0.12). Postoperative secondary gastric cancer was encountered in eight patients (1.6 %) in the PPG group and four patients (0.8 %) in the DG group. No significant differences in either overall survival, relapse-free survival, or the occurrence of secondary gastric cancer were observed between the two groups. Conclusions: Given the adequate estimation of the clinical tumor stage, the oncological safety of PPG for clinical T1N0 gastric cancer in the middle portion of the stomach was comparable to that of DG.