Chemoprevention of gastric dysplasia: Randomized trial of antioxidant supplements and anti-Helicobacter pylori therapy

Background: Previous research has identified a high risk of gastric carcino ma as well as a high prevalence of cancer precursor lesions in rural popula tions living in the province of Narino, Colombia, in the Andes Mountains. M ethods: A randomized, controlled chemoprevention trial was conducted in sub jects with confirmed histologic diagnoses of multifocal nonmetaplastic atro phy and/or intestinal metaplasia, two precancerous lesions. Individuals wer e assigned to receive anti-Helicobacter pylori triple therapy and/or dietar y supplementation with ascorbic acid, p-carotene, or their corresponding pl acebos. Gastric biopsy specimens taken at baseline were compared with those taken at 72 months, Relative risks of progression, no change, and regressi on from multifocal nonmetaplastic atrophy and intestinal metaplasia were an alyzed with multivariate polytomous logistic regression models to estimate treatment effects, All statistical tests were two-sided. Results: All three basic interventions resulted in statistically significant increases in the rates of regression: Relative risks were 4.8 (95% confidence interval [CI] = 1.6-14.2) for anti-H. pylori treatment, 5.1 (95 % CI = 1.7-15.0) for p-c arotene treatment, and 5.0 (95% Cf = 1.7-14.4) for ascorbic acid treatment in subjects with atrophy. Corresponding relative risks of regression in sub jects with intestinal metaplasia were 3.1 (95% CI = 1.0-9.3), 3.4 (95% CI = 1.1-9.8), and 3.3 (95% CI = 1.1-9.5), Combinations of treatments did not s tatistically significantly increase the regression rates. Curing the H. pyl ori infection (which occurred in 74% of the treated subjects) produced a ma rked and statistically significant increase in the rate of regression of th e precursor lesions (relative risks = 8.7 [95 % CI = 2.7-28.2] for subjects with atrophy and 5.4 [95% CI = 1.7-17.6] for subjects with intestinal meta plasia), Conclusions: In the very high-risk population studied, effective a nti-tl; pylori treatment and dietary supplementation with antioxidant micro nutrients may interfere with the precancerous process, mostly by increasing the rate of regression of cancer precursor lesions, and may be an effectiv e strategy to prevent gastric carcinoma.