Gastric cancer epidemiology and risk factors

Background

: The published epidemiological studies of chronic Helicobacter pylori infection and gastric cancer yield conflicting results, so there is uncertainty as to whether any material association exists and, if so, how strong it is



Aim

: To review these studies quantitatively



Methods

: A systematic review of sero-epidemiological studies published before 1998 of H pylori and gastric cancer, as identified by computer-assisted literature searches of relevant journals, reference lists and discussions with authors All relevant studies identified were included, subdivided by study design The following was abstracted from published reports: adjusted odds ratio (or, in prospective studies, the risk ratio) and confidence interval, study design, type of controls, mean age, mean duration of follow-up, assay methods, location of study, and degree of adjustment for confounders



Results

: The 34 retrospective studies included in total 3300 gastric cancers, but their controls were of uncertain validity The 10 ‘nested’ case–control comparisons in prospective studies included in total only 800 gastric cancers, and combined analysis of them yielded a risk ratio of 25 (95% CI: 19–34; 2P < 000001) for gastric cancer in people seropositive for H pylori antibodies



Conclusions

: The prospective studies suggest that gastric cancer is 2 or 3 times as common in those chronically infected by H pylori, but to help investigate causality, further observational studies are still needed, as are large-scale randomized trials of whether antibacterial regimens reduce the eventual incidence of gastric cancer

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2036.1999.00546.x

Helicobacter pylori infection and gastric cancer: systematic review of the epidemiological studies

Helicobacter pylori eradication has the potential to prevent gastric cancer : a state-of-the-art critique

This paper will briefly review the evidence for the role of Helicobacter pylori infection in the aetiology of gastric cancer and consider the implications of this relationship. The critical issue of whether H. pylori eradication may play a part in a strategy for the prevention of gastric cancer will then be discussed. Although this paper will largely be concerned with epidemiological evidence, it should be emphasised that an understanding of the mechanistic basis to the H. pylori-cancer relationship is also advancing rapidly and this area will be reviewed in the paper by Correa elsewhere in this issue.

Helicobacter pylori infection and cancer.

Gastric malignancies have been closely linked to infection of the gastric mucosa with Helicobacter pylori, but the individual factors involved in the multistage process of tumor development are still poorly understood H pylori evades the host defense system and causes persistent infection and chronic inflammation Immune activation leads to DNA damage by the release of oxygen and nitrogen radicals Ongoing tissue repair mechanisms and the secretion of cytokines and growth factors, as well as bacterial effector molecules, cause disturbances in the balance between epithelial cell proliferation and apoptosis, promote the accumulation of potential oncogenic mutations, and support neovascularization and tumor growth In addition, H pylori might hamper the development of an efficient antitumor immunity and provoke immune-mediated pathology This review summarizes the recent progress in the understanding of the intimate bacteria-host relationship and the mechanisms by which H pylori may promote the process of tumor development

Persistent infection with Helicobacter pylori and the development of gastric cancer.

Helicobacter pylori screening and gastric cancer

, optimized to detect as little as 0.01pg of genomic DNA (or about a dozen organisms) (6). DNAhad been extracted from the buffy coat samples of 77 healthyindividuals for a genetic study of myocardial infarction; 52 ofthese individuals were known to be strongly seropositive forimmunoglobulin G antibodies to

John Danesh

Papers

Helicobacter pylori screening and gastric cancer

FAST-TRACK COMMUNICATION Is Helicobacter pylori a Factor in Coronary Atherosclerosis?