Gastric cancer is an important global public health issue in Eastern European regions,
where the burden of the disease is substantial. There is sufficient epidemiological and
experimental evidence that supports a causal link between H. pylori and gastric cancer.
However, there is still limited evidence from clinical trials to prove whether H. pylori
eradication with antimicrobial therapy is the approach of choice in entire infected
populations or only in selected groups to reduce the risk of gastric cancer and whether
eradication at advanced stages of atrophy is effective among these patients. The current
European and global guidelines are proposing screening with pepsinogen tests as the best
available tool to identify the individuals at increased risk for cancer development, yet
there is insufficient evidence available on how effective these tests are in organized
cancer screening settings.
We therefore propose to conduct a multi-center randomized trial in Latvia, Belarus and
Russia, areas with high burden of the disease, with the main objective of evaluating if
H. pylori screening followed by eradication in participants with positive result and
endoscopy of those with serological evidence of atrophic gastritis can reduce gastric
cancer mortality. The proposed trial will also investigate retrospectively if groups with
chronic atrophic gastritis can select subjects who require treatment to achieve
comparable gastric cancer reduction. Ultimately, this study will have the potential to
find effective prevention strategies through identifying appropriate target groups that
could get most benefits from the treatment.
The aim of this study is to search for new intervention strategies to decrease mortality
from gastric cancer in high-risk areas.
The primary objective of the study is to determine if H. pylori screening followed by
eradication of positive subjects and endoscopic follow-up of those with serological
evidence of atrophic gastritis reduces mortality from gastric cancer in a high risk
population among 40-64 years old subjects.
The secondary objectives are:
To determine retrospectively if biomarkers of chronic atrophic gastritis or others
can select the group of subjects who require treatment to achieve gastric cancer
reduction comparable to the primary objective.
To evaluate the rationale for volatile marker testing in exhaled breath for early
identification of lesions in the stomach as well as other conditions related to
increased risk.
To evaluate the role of diet, lifestyle factors and environmental factors in the
development of gastric lesions.
To evaluate the impact of H. pylori eradication on selected medical conditions
potentially associated with the infection (e.g. obesity, inflammatory bowel disease,
dementia, circulatory diseases and esophageal diseases)
Methods: Approximately 30,000 men and women will be recruited into a randomized study.
Eligible subjects between 40-64 years of age at entry who are residents in high gastric
cancer incidence areas will be invited to participate in the trial by visiting one of the
study clinics set up specifically for this trial.
For eligible participants who agree to participate and sign informed consent, a risk
factor questionnaire will be administered and a complete medical evaluation will be
performed at baseline.
Participants will be randomly assigned to either Group 1 (50%) or Group 2 (50%). Among
those assigned to Group 1, H. pylori screening by detecting immunoglobulin G (IgG) group
antibodies in plasma/serum and pepsinogen test will be performed. According to the
results of the tests, participants will be assigned to H. pylori eradication treatment or
upper endoscopy. Participants with serological evidence of atrophic gastritis (low
pepsinogen I/II ratio) will undergo upper endoscopy with appropriate biopsy sampling as
well as further follow-up with endoscopy according to MAPS (Management of precancerous
conditions and lesions in the stomach) guidelines. H. pylori positive individuals will be
offered standard eradication treatment as appropriate. From subjects in this group,
breath samples will also be collected for volatile markers study by research nurses or
junior physicians.
Participants assigned to Group 2 (50%) will constitute the control group, after having
had a medical evaluation at the time of recruitment. During the follow-up period this
group will be offered to consult a specialist when required due to clinical symptoms.
Both Group 1 and Group 2 will be offered fecal occult blood test (FOBT) as a benefit of
study participation. Any participants who show a positive FOBT result will be referred to
colonoscopy.
All the trial participants including Group 2 will be followed up at least for 15 years to
collect systematic information on medical conditions, in particular gastric cancer and
cause of death. A follow-up telephone call /alternative communication will be made every
5 years for outcome assessment.
The general study is preceded by a pilot-study that was conducted from October 2013 to
December 2016 to test the assumptions as well as the tools and functionality of the study
infrastructure. According to the results of the pilot study, required infrastructure and
tools planned in the general study will be adapted accordingly.
Endpoints: The primary endpoint for our trial will be the mortality difference from
gastric cancer between Group 1 and Group 2 at 15 years or when enough cases accumulate to
demonstrate a statistical difference between the groups.
In addition to the mortality difference from gastric cancer between the two groups, other
endpoints required to achieve the secondary objectives are listed below:
The difference in gastric cancer incidence between Group 1 and Group 2
The all-cause mortality difference between Group 1 and Group 2
The difference in incidence and mortality of medical conditions between Group 1 and
Group 2
Sensitivity and specificity of pepsinogen tests to detect atrophy
The proportion of gastric cancers arising in patients with non-atrophic vs. atrophic
gastritis
The proportion of cancers arising in patients with atrophy, but negative for H.
pylori infection
The difference in incidence of gastric cancer in the group with successful
eradication when compared to those refusing/failing eradication within Group I
The proportion of gastric cancer cases being identified during scheduled follow-up
endoscopy out of the total number of cases in the follow-up group
The differences in the test performance and disease prevalence between ethnic groups
The performance (sensitivity, specificity, overall accuracy) of volatile marker
testing approach to diagnose gastric cancer as well as premalignant lesions in the
stomach
A pilot study with 3,455 participants was started in October 2013 and completed in
December 2016 in Latvia.