This prospective non-interventional study is being conducted as part of the EU4Health project Eurohelican. The main goal of this pilot study is to evaluate the feasibility and acceptability of implementing the proposed "test-and-treat" screening program on a population-based sample. Participants will be randomly selected from a younger population registered at the primary level of care and tested for the presence of active infection with Helicobacter pylori (H. pylori). Infected participants will undergo a bismuth-based quadruple treatment with antibiotics and a proton pump inhibitor, and will be controlled for eradication success by taking the urea breath test (UBT). A number of other participant outcomes will be also measured to provide additional pro et contra argumentation for the potential future implementation of a population-based test-and-treat screening program in Slovenia. Research reports will be disseminated and results will be presented to the public and scientific community to foster future developments in gastric cancer prevention.

Gastric cancer remains an important public health issue due to its high incidence rate and relatively low five-year survival rate. H. pylori infection has been found to be the main cause of gastric cancer and is responsible for 89% of non-cardia gastric cancers. There is also evidence that H. pylori eradication significantly reduces the incidence and mortality due to gastric cancer. According to the proposal based on available data, the population-based test-and-treat screening program may be the best available evidence-based intervention to prevent the occurrence of gastric cancer. In its recommendations from September 9th 2023, the European Council also supported the implementation of a screening program particularly in European regions with an increased prevalence of H. pylori and incidence of gastric cancer. The aim of this study is to scientifically evaluate the feasibility, acceptability and effectiveness of the proposed population-based test-and-treat strategy for the eradication of H. pylori infection.

The proposed test-and-treat strategy is targeted at the population around the age of 30 years who are infected with H. pylori and predominantly asymptomatic. The main questions it aims to answer are:

• Is the proposed population-based H. pylori test-and-treat strategy feasible and acceptable in a community health service setting?
• Is the proposed population-based H. pylori test-and-treat strategy effective in a community health service setting?
• What is the profile of adverse events in the treated participants?

Participants will be randomly selected from the population pool of individuals aged 30-34 years who have a chosen personal physician at Community Healthcare Center dr. Adolf Drolc Maribor (HCM). Enrolled participants who will give their informed consent will be interviewed by a registered nurse regarding risk factors for developing H. pylori infection and selected lifestyle habits. In addition, serology testing for the presence of H. pylori antibodies will be performed on all participants. Participants with a positive serology result will be given a confirmatory urea breath test (UBT). Those participants with a confirmed active H. pylori infection will be treated with bismuth-based quadruple therapy, and the success of eradication will then be verified by UBT one month after the treatment. Participants with a positive result of the second UBT will be treated again with a second-line modified bismuth-based quadruple therapy, and the success of eradication will be verified by UBT. Compliance with testing and treatment, treatment outcomes, adverse events and reasons for withdrawing participation will be monitored for each of the participants. The feasibility and sustainability of the proposed test-and-treat strategy will be evaluated using several key performance indicators that follow the structure of five principal areas of feasibility. Data will be entered into the REDCap online survey application and analyzed using IBM SPSS Statistics software.

The results of this study will enable to potentially scale up the project to the national level and present a potential model for the implementation of this strategy in Europe. Second, the results will contribute to the implementation of the Europe's Beating Cancer Plan goal of preventing gastric cancers caused by H. pylori infections. Finally, this study will provide additional real-world data for the preparation of Expert Working Group Report of the International Agency for Research on Cancer of the World Health Organization (IARC/WHO), which will include a minimum set of standards for the implementation of a population-based screening program at the international level.

Inclusion Criteria:

• Individuals aged 30-34 years,
• Individuals who have a chosen personal physician at HCM,
• Individuals who sign an informed consent to participate, and
• Individuals who do not have a congenital or acquired intellectual disability.

Exclusion Criteria:

• Individuals younger than 30 years or older than 34 years,
• Individuals who do not have a chosen personal physician at HCM,
• Individuals who do not sign informed consent for participation,
• Individuals with intellectual or developmental limitations who are unable to provide a fully-informed consent to participate (based on the assessment of the patient's primary care team)
• Individuals who were previously treated for H. pylori infection, and
• Individuals with a history of partial of total gastric resection due to benign or malign lesions.

The primary pool of potential participants is composed of younger individuals of both sexes between 30 and 34 years of age with a registered chosen personal physician at HCM. A single non-interventional cohort of 4,000 individuals will be randomly selected using Monte-Carlo sampling method. All selected individuals in a sample will be invited to participate. If the individual expresses interest in participating, the primary care team staff will decide whether or not to enroll the individual in the study based on the inclusion and exclusion criteria.