A Randomized Multi-Intervention Trial to Inhibit Precancerous Gastric Lesions in Lingu, Shandong Province
Status:
Completed
Trial end date:
1996-06-10
Target enrollment:
Participant gender:
Summary
The Division of Cancer Epidemiology and Genetics is conducting a collaborative randomized
multi-intervention trial with the Beijing Institute for Cancer Research to evaluate the
etiologic role of Helicobacter pylori, garlic, and certain micronutrients in the multi-step
process of gastric carcinogenesis. The primary endpoint will not be cancer, but rather the
precancerous lesions severe chronic atrophic gastritis, intestinal metaplasia, and dysplasia.
The study is designed to detect a stabilizing or mild decrease in the expected age-related
progression of precancerous lesions over the course of the trial. Thus the trial can be
considered a study of the potential inhibitors of the process of gastric carcinogenesis. The
trial will also provide an evaluation of therapy for H. pylori, including an assessment of
reinfection rates, a critical need for formulating strategies for infection control in China
and other developing countries. Participating in the trial are approximately 3400 adults aged
35-70 who were part of an ongoing survey of precancerous gastric lesions in 13 Linqu villages
in Shandong Province. Linqu appears to be an ideal setting for the trial since stomach cancer
rates are among the highes in the world, precancerous gastric lesions are prevalent, and the
population is stable and well characterized. These individuals will be randomly assigned
(taking H. pylori positivity into account) into 8 intervention groups according to a 2(3)
factorial design. The interventions are: 1) initial treatment of H. pylori infection with
ameprazole and amoxicillin followed by 2) daily supplementation with a combination of
alpha-tocopherol, vitamin C, and selenium; and 3) daily supplementation with garlic extracts.
No serious side effects have been seen from any of the interventions to date. The study staff
will continue to monitor for possible adverse reactions and the population will receive
routine medical care follow-up throughout the course of the trial.
As part of the ongoing study in Linqu, all participants received an endoscopic exam in the
fall of 1994. Repeat gastroscopic exams with biopsies at 7 standard gastric sites will be
conducted during March to May, 1999 and March to May, 2003 to detect early cancers and to
evaluate gasatric mucosal status. The subjects will be categorized according to the most
advanced lesions detected in all biopsies and assigned a severity score. The three major
endpoints for analysis will be: 1) prevalence of dysplasia or cancer 2) prevalence of sever
chronic atrophic gastritis, intestinal metaplasia, dysplasia, or cancer; and 3) average
severity score.