Comparison of the overall survival of proximal and distal gastric cancer after gastrectomy: a systematic review and meta-analysis

BACKGROUND: The aim of this study was to investigate the overall survival (OS) between proximal gastric cancer (PG) and distal gastric cancer (DG) patients after gastrectomy. METHODS: Articles on the prognostic study of PG and DG patients after gastrectomy were collected from the PubMed, EMBASE, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, and VIP databases from the date of establishment until December 2020. The data were statistically analyzed by Stata software (version 11.0, StataCorp). RESULTS: A total of 10 articles met the inclusion criteria. Meta-analysis showed that the 1-, 3- and 5-year OS rates of PG patients were significantly lower than those of DG patients (RR = 0.898, 95% CI: 0.825 to 0.977, P = 0.013; RR = 0.802, 95% CI: 0.708 to 0.909, P = 0.001; RR = 0.736, 95% CI: 0.642 to 0.844, P = 0.000). After subgroup analysis according to different countries, the combined RR values of were as follows: 1-year OS: eastern countries: RR = 0.966, 95% CI: 0.944 to 0.988, P = 0.003, western countries: RR = 0.687, 95% CI: 0.622 to 0.759, P = 0.000; 3-year OS: eastern countries: RR = 0.846, 95% CI: 0.771 to 0.929, P = 0.000, western countries: RR = 0.742, 95% CI: 0.399 to 1.382, P = 0.348; and 5-year OS: eastern countries: RR = 0.798, 95% CI: 0.716 to 0.889, P = 0.000, western countries: RR = 0.646, 95% CI: 0.414 to 1.008, P = 0.054. CONCLUSION: In terms of 1-, 3-, and 5-year OS, PG patients had lower rates than DG patients and the eastern countries/western countries subgroup, but there were no significant differences in 3- and 5-year OS for the western countries. These results merit further clinical validation in future studies. (Registration ID: UMIN000040393; Date of registration: 2020/05/13)