Drawbacks to screening include the risks of radiation (if imaging is performed) and those associated with endoscopy. Screening is unlikely to be cost-effective in low-risk populations [20], and is only of value if it detects risk factors that can be modified or early-stage disease that can be treated effectively [21].

The question for CVID patients is whether a higher risk of gastric cancer can be defined in particular groups. H. pylori is a Gram-negative bacterium and is implicated in the development of chronic gastritis, peptic ulceration, gastric carcinoma and MALT lymphoma. In 1994 the World Health Organization (WHO) classified H. pylori as a class I (or definite) carcinogen [22]. A multi-step model for the pathogenesis of LY294002 manufacturer gastric carcinoma has been proposed from epidemiological and pathological studies [23,24]. Chronic gastritis and gastric atrophy result from infection with H. pylori, and a higher gastric pH appears to permit the proliferation of nitrate-reducing anaerobic bacteria, resulting in the production of N-nitroso compounds [25], promoting carcinogenesis through intestinal metaplasia and

dysplasia to carcinoma [26]. This suggests that gastric pathology such as gastritis, gastric atrophy, metaplasia or dysplasia might be regarded as precancerous NVP-AUY922 lesions. Data from prospective studies suggest that in the general population H. pylori infection confers a two- to ninefold increased risk of gastric cancer. A meta-analysis of three prospective studies Edoxaban into the risk of gastric cancer attributable to H. pylori demonstrated a relative risk of 9 in subjects followed for up to 25 years [27], while a systematic review of nested case–control studies, which included 800 gastric cancer cases, found only a two- to threefold increased risk (95% CI 1·9–3·4) of gastric cancer in patients chronically infected with H.

pylori[28]. More recently, an analysis of 12 case–control studies nested within prospective cohorts, which examined H. pylori serology before gastric cancer diagnosis in 1228 non-cardia gastric cancer cases, found that the relative risk of non-cardia cancers associated with prior H. pylori infection was 5·9 (95% CI 3·4–10·3); however, there was no increased risk of cancers of the gastric cardia [29]. This means that H. pylori infection should be taken into account in any surveillance programme. Pernicious anaemia is a chronic autoimmune disease in which atrophic gastritis, typically sparing the antrum, results in a lack of intrinsic factor and vitamin B12 malabsorption with megaloblastic anaemia.