Effectiveness of Gastric Cancer Endoscopic Screening in Intermediate-Risk Countries - Protocol for a Systematic Review and Meta-Analysis.

Background: Gastric Cancer (GC) is the fifth neoplasia with the highest incidence worldwide and the fourth with the highest mortality and its geographical distribution isn't homogeneous with high risk, intermediate-risk (IR) and low-risk areas. Advanced stage at diagnosis is related with high mortality of GC, but early detection greatly increases the chances of successful treatment. Upper endoscopy with biopsy is the gold-standard for diagnosis of GC. In IR countries, several studies have been developed to determine the relevance of endoscopic screening and how it could be developed. However most Western Societies continue to recommend screen only in selected populations with high-risk factors for GC. Furthermore, there are no systematic reviews on GC endoscopic screening in IR countries.

Objective: This review aims to determine the effectiveness and economic viability of endoscopic GC screening in IR countries, that will answer the research question: What is the effectiveness of endoscopic screening for GC in IR countries?

Methods: We will include randomized controlled trials, non-randomized controlled trials, cohort studies, case-control studies, cross-sectional studies and economic studies focusing on endoscopic screening of GC in asymptomatic population of IR countries. The search will be conducted in MEDLINE, SCOPUS, EMBASE and Web of Science. Other grey literature sources will be additionally searched. Studies published in English, Portuguese or Spanish published until September 2024 be included. Two independent reviewers screen the titles and abstracts of all search results. The selected studies will then be fully analyzed and the data will be collected and coded in a database. To minimize the risk of bias, the included studies will undergo a quality analysis according to Cochrane risk of bias tools, RoB 2 of randomized trials and ROBINS-I for non-randomized trials, QUADAS-2 for diagnostic test accuracy and the National Heart, Lung and Blood Institute study quality assessment tools for observational cohort, cross-sectional and case-control studies. The data collected will be catalogued in 2 categories: efficacy/effectiveness data and economic data, and separate meta-analyses will be performed for each category.

Results: This systematic review is expected to provide results on the efficacy, effectiveness and cost-effectiveness of endoscopic screening in an IR population. It is expected that the presentation of these results will shed light on the relevance of endoscopic GC screening in IR countries. The review is currently in the full-text screening stage and will be published in the first quarter of 2025.

Conclusions: To our knowledge, this review will be the first to provide evidence on the effectiveness of endoscopic GC screening in IR countries. In doing so, we believe we will help guide future research, inform health care decisions and policy makers in this area, and support future decisions to implement GC screening programs in this type of population.

Clinicaltrial: Prospero: CRD42024502174.