Effect of Helicobacter pylori eradication on the incidence of gastric cancer: a systematic review and meta-analysis
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Helicobacter pylori (H. pylori) is considered to be the most important risk factor for gastric cancer (GC). The International Agency for Research on Cancer reported that H. pylori eradication could reduce the risk of developing GC. Several clinical studies have investigated this relationship as well; however, their results are inconsistent owing to the varied inclusion criteria. To address the effect of H. pylori eradication on GC incidence, we conducted a comprehensive meta-analysis with several subgroup analyses to resolve these inconsistencies.
We searched MEDLINE and Ichushi-Web to identify randomized control trial and cohort study articles (English or Japanese) through December 2016. Manual searches were also conducted to identify unlisted references in these databases. Eligible studies reported GC incidence as an outcome, with comparisons between H. pylori eradication and control groups. Subgroup analyses were conducted by country, conditions at baseline, and follow-up periods.
We selected 28 studies among 1583 references in the databases and 4 studies by manual searches. The H. pylori eradication group showed significantly lower risk of GC [odds ratio (OR) 0.46; 95% confidence interval 0.39–0.55]. The subgroup analyses indicated that the beneficial effect of eradication was greater in Japan (OR 0.39; 95% CI 0.31–0.49), particularly among those with benign conditions (OR 0.32; 95% CI 0.19–0.54), although none of them was statistically significant. However, reduction of gastric cancer after eradication was significantly greater (p = 0.01) in the groups with long-term (5 years or longer) follow-up (OR 0.32; 95% CI 0.24–0.43) as compared to those with shorter follow-up (less than 5 years) (OR 0.55; 95% CI 0.41–0.72).
Real world data showed that large-scale eradication therapy has been performed mostly for benign conditions in Japan. Since eradication effects in preventing gastric cancer are conceivably greater there, GC incidence may decline faster in Japan than expected from the previous meta-analyses data which were based on multi-national, mixed populations with differing screening quality and disease progression.
KeywordsHelicobacter pylori eradication Systematic review Meta-analysis Gastric cancer prevention
The author would like to thank Tomomi Takeshima, PhD, and Wentao Tang, PhD, employees of Milliman, for performing the literature search, developing the first draft (TT) and analyzing data (WT). The author would also like to thank Shinzo Hiroi, PhD, at the time employed by Takeda Pharmaceutical Co., Ltd., for contribution to study design and interpretation of data and to Akihito Uda, Takeda Pharmaceutical Co., Ltd., for coordinating this study. I would like to thank Editage (http://www.editage.jp) for English language editing.
Compliance with ethical standards
Human rights statement
This study is a meta-analysis on the published literatures and does not contain any studies with human or animal subjects.
No individual patient data were used for the analysis, which should exempt this study from the requirement of obtaining informed consents.
Conflict of interest
KS has received research grants from Eisai Pharma, Daiichi Sankyo Pharma, and Takeda Pharmaceutical Co., Ltd, and received lecture fees from Astellas Pharma, Fujifilm, EA Pharma, and Takeda Pharmaceutical Co., Ltd. This study was funded by Takeda Pharmaceutical Co. Ltd.
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