Systematic review and meta‐analysis. Risk of gastric cancer in patients with first‐degree relatives with gastric cancer

Background: Gastric cancer ranks fourth in terms of global cancer-related deaths. Timely identification of high-risk populations is crucial to reduce mortality. Although a family history of gastric cancer increases risk, European and British guidelines report weak recommendations and low-quality evidence about the management of these patients. Aim: To quantify the association in case–control studies of patients with gastric cancer with first-degree relatives with gastric cancer compared to those who do not. Methods: We conducted a systematic review and meta-analysis of case–control studies up to November 2023. Data extraction was performed independently by two reviewers. The heterogeneity of effects across studies was quantified by I2. We calculated odds ratios (OR) with 95% confidence intervals (CI) using random effects models. Results: We included 30 studies in the systematic review. In all studies, a first-degree family history of gastric cancer represented a risk factor for gastric cancer. We included 21 studies on the risk of gastric cancer. There was a significantly increased association between gastric cancer and having first-degree relative(s) with gastric cancer, but with significant heterogeneity among studies (OR = 2.92; 95% CI 2.402–3.552; p< 0.001; I2= 81.85%; p< 0.001). Conclusion: This meta-analysis highlights the relevance of patients' family history of gastric cancer and the importance of this risk factor for the early detection of neoplastic conditions.