Gastric cancer:: Epidemiology, risk factors and significance of nutrition

In spite of decreasing incidence and mortality in industrialized countries, gastric cancer is still the second most common malignancy worldwide. The etiology of gastric cancer is largely unknown and is most likely multifactorial. Intestinal type cancer evolves in distinct stages. It was suggested that chronic atrophic gastritis is the basis of the development of malignancy. The main cause of chronic atrophic gastritis is the infection with Helicobacter pylori, but the precise mechanism by which this bacterium cause cancer is unknown. Other conditions associated with mucosal atrophy are gastric resection and pernicious anemia. Cancer incidence increases 1.5- to 3-fold 15 to 20 years after gastric resection. The risk of patients with type A gastritis is about 2- to 3-fold increased. The role of nutritional factors for the development of gastric cancer is conflicting. Some foods (cured or smoked meat or fish) may increase the exposure to carcinogens. Also decreased intake of 'protective' nutrients (ie. antioxidants like ascorbic acid) may increase cancer risk. Most of the reported studies were conducted in the pre-Helicobacter era and are thus of limited value. Recent studies from China indicate that garlic and green tea appear to protect against gastric cancer. The incidence of persons drinking larger amounts of green tea is by 25% lower than those who do not drink tea.