DIFFICULTY IN ERADICATING HELICOBACTER-PYLORI IN A POPULATION AT HIGH-RISK FOR STOMACH-CANCER IN VENEZUELA

The bacterium Helicobacter pylori (HP) has been implicated in the etio logy of precancerous lesions of the stomach and there is evidence sugg esting that it may influence the efficacy of chemoprevention of gastri c cancer with vitamin C. Eradication seldom has been attempted in popu lations from developing countries, with a high prevalence of HP freque ntly resistant to metronidazole. A randomized, double-blind, controlle d trial to evaluate the efficacy of colloidal bismuth subcitrate (120 mg q.i.d.) and amoxycillin (500 mg q.i.d.) in eradicating HP was condu cted in 220 subjects drawn from a population with a high prevalence of metronidazole-resistant HP in Tachira state, Venezuela. One month aft er completion of two weeks' treatment, eradication rates of 6.5 percen t in the treatment group and two percent in the placebo group were est imated on the basis of HP diagnosis in biopsies, and of 13.9 percent c ompared with 3.9 percent on the basis of a C-14-urea breath test, alth ough the negative predictive value of the breath test was very low com pared with HP diagnosis in biopsies. In the treatment group, particula rly among males, a significant decrease in bacterial load was detected . Reasons for failure of treatment in high HP-prevalence areas are dis cussed, and it is suggested that primary prevention of HP infection ma y be the optimal approach to reducing levels of stomach cancer in thes e high-risk groups.