Pathological and oncological outcomes of pylorus-preserving versus conventional distal gastrectomy in early gastric cancer: A systematic review and meta-analysis

Abstract

Abstract Background: Pylorus-preserving gastrectomy (PPG) is a function-preserving surgery for the treatment of early gastric cancer (EGC) in the middle third of the stomach. According to the literature reports, PPG decreased decreases the incidence of dumping syndrome, bile reflux, gallstone formation, and nutritional deficit in comparisoned with conventional distal gastrectomy (CDG). However, the debates about PPG has have been dominated by the incomplete lymphadenectomy and oncological safety. We carried out a systematic review and meta-analysis to evaluate the pathological and oncological outcomes of PPG.Methods: The protocol was registered in PROSPERO under number CRD42022304677. Databases including PubMed, Embase, Web of science Science and the Cochrane Register of Controlled Trials were searched before February 21,2022. The outcomes included the pooled odds ratios (ORs) for dichotomous variables and weighted mean differences (WMDs) for continuous variables. For Aall outcomes, were 95% calculated with 95% confidence intervals (CiCIs) were calculated. Meta-analysis was performed using STATA software (Stata 14, Stata Corporation, Texas) and Review Manager 5.4. Results: A total of 4500 patients from 16 studies were included. Compared with the CDG group, the PPG group has had less fewer lymph nodes harvested (WMD=-3.09; 95% CI -4.75 to -1.43; P<0.001). Differences of in the number of resected lymph nodes were observed in at stations No.5, No.6, No.9 and No.11p stations. There were no differences in lymph nodes metastasis of at each station. Shorter proximal resection margins (WMD= -0.554; 95% CI, -0.999 to -0.108; P=0.015) and distal resection margins (WMD= -1.569; 95% CI -3.132 to -0.007; P=0.049) were observed in the PPG group. There were no significant differences in pathological T1a stage (OR=0.99; 95% CI 0.80 to 1.23; P=0.88), T1b stage (OR=1.01; 95% CI 0.81 to 1.26; P=0.88), N0 stage (OR=0.97; 95% CI 0.63 to 1.48; P=0.88), tumor size (WMD = -0.10; 95% CI, -0.25 to 0.05; P = 0.187), differentiated carcinoma (OR=1.04; 95% CI 0.74 to 1.47; P=0.812) or signet ring cell carcinoma (OR=1.22; 95% CI 0.90 to 1.64; P=0.198). No significant differences were observed between the groups in terms of overall survival (HR=0.63; 95% CI 0.24 to 1.67; P=0.852HR=0.22 95%CI 0.01 to 6.69; P=1.000) and or recurrence recurrence-free survival (HR=0.29; 95% CI 0.03 to 2.67; P=0.900HR=0.31; 95%CI 0.00 to 24.35; P=0.687)..Conclusions: The meta-analysis of existing evidence demonstrated that PPG the survival outcomes of PPG may be had comparable survival outcomes withto those of CDG. However, PPG harvested lessfewer lymph nodes at stations in No. 5, No. 6, No. 9 and No. 11p were harvested with PPG stations. We also found that PPG has shorter proximal resection margins and distal resection margins for PPG, meaning more remnant stomach would be preserved in PPG.