A possible role of iron deficiency in gastric cancer in Colombia.

Abstract

Through the efforts of Correa, Cuello, Haenszel, Tannenbaum and others it was learned that the incidence of gastric cancer in certain areas of Narino (Colombia) was among the highest in the world. These areas of high risk for gastric cancer were adjacent to an area of substantially lower risk. Gastric biopsies from healthy volunteers residing in the "high risk" area exhibited a greater incidence of superficial gastritis and chronic atrophic gastritis with and without intestinal metaplasia than those from the low risk area. The latter pathological finding is considered to be a precursor lesion to gastric cancer. Volunteers from the "low risk" area as well as individuals from Cali in the coastal region and Cartegena on the coast, also exhibited a similar spectrum of pathology but at a substantially reduced frequency. Natives of both cities were also at lower risk for gastric cancer than inhabitants of Narino. It was found that the water supply of the "high risk" area contained a higher concentration of nitrate than water in the "low risk" area. Correa et al. hypothesized that the high nitrate concentrations of well water contributed to the formation of N-nitroso compounds in the stomachs of these individuals early in life. The occurrence of this putative carcinogen in combination with the abrasive action of dietary grains contributed to a series of mutations in the gastric epithelium progressing through a sequence of pathologic changes, loss of gastric acid and culminating in gastric cancer. In the current report individuals in a Medellin population who were admitted with abdominal complaints and were found to be iron deficient exhibited the same spectrum of gastric pathology described by previous investigators. Superficial gastritis, chronic atrophic gastritis and achlorhydria have also been described in association with chronic iron deficiency (and/or associated nutritional defects) per se. The development of these lesions are likely to occur within the first two decades of life when iron requirements are maximal. It is suggested that these changes preceed the development of gastric cancer. Bacterial colonization of the achlorhydric stomach may facilitate nitrate reduction and the formation of a putative carcinogen N-nitroso compound(s) from nitrate in the water supply. Additionally, the effects of chronic iron deficiency on host immune defense may compromise these mechanisms and permit tumor growth with minimal immune intervention.