Controversias entre la infección por Helicobacter pylori y la epidemiología del cáncer gástrico

Helicobacter pylori infection is thought to be associated with the development of gastric cancer. Indeed several studies have postulated, tested and supposedly proven this association. Unfortunately many of these studies have actually produced conflicting results. It sometimes seems that the association exists and is strong, but at other times there is uncertainty as to whether any material association between this pathogen and gastric cancer can be proven. At least 50% of all studies designed to prove this association have generated results with a negative association between Helicobacter pylori and gastric cancer Even those that have had positive association results are not reproducible, suggesting a lack of consistency. Moreover, epidemiological evidence alone is inadequate to prove causality. In fact, the few animal experiments that have been conducted to establish a definite link with gastric cancer have not been so successful in doing so. At present therefore, Helicobacter pylori does not seem to have a "cause and effect" association with gastric cancer. We think that the classification of this pathogen by IARC in 1994 as a Group 1 human carcinogen was premature and a re-classification of Helicobacter pylori into a more appropriate category may be warranted due to lack of consistent evidence.