Aetiology

Aetiology

Gastric cancer is a multifactorial disease. Epidemiological studies point to a role for H. pylori ; however, there is insu ffi cient evidence to support eradication programmes in asymptomatic patients . H. pylori seems to be principally associated with carci noma of the body , stomach and distal stomach rather than the proximal stomach. Patients with pernicious anaemia and gastric atrophy are at increased risk, as are those with gastric adenomatous polyps. P atients who have had peptic ulcer surgery , particularly those w ho have had drainage procedures such as Billroth II or Pólya gastrectomy , gastroenterostomy or pyloroplasty , are at approximately four times the average risk; this is thought to be related to bile reflux and intestinal metaplasia. Carcinoma is associated with cigarette smoking and dust ingestion from a variety of industrial processes. Diet appears to be important, as illustrated by the example of the decline in the incidence of gastric cancer among Japanese families living in the USA. The high incidence of gastric cancer in some pockets in China is probably environmental and probably diet related. Excessive salt intake, deficiency of antioxidants and exposure to N -nitroso compounds are also related. The aetiology of proximal gastric cancer remains an enigma. It is not associated with H. pylori but is associated with obesity and higher socioeconomic status. Genetic factors are also important but not fully elucidated (see /uni00A0 The molecular pathology of gastric cancer ).