Family History of Colorectal Cancer and the Risk of Colorectal Neoplasia: A Systematic Review and Meta-Analysis.

Introduction: Although there is enough pooled evidence supporting the positive association between family history of colorectal cancer (CRC) in first-degree relatives (FDRs) and the risk of CRC, synthesized data on its association with the risk of other colorectal neoplasia are lacking. Therefore, we aimed to systematically assess this issue.

Methods: We searched PubMed, Web of Science, and Embase from database inception through May 9, 2024, to identify observational studies investigating the association between family history of CRC in FDRs and the risk of colorectal neoplasia (excepting CRC). Adenoma, nonadvanced adenoma (NAA), advanced adenoma (AA), and advanced neoplasia (AN) were further chosen as main outcomes because of data availability. Random-effects model was used for data synthesis. Subgroup meta-analyses were performed to evaluate the robustness of results.

Results: Of 5,172 initial records screened, 75 studies (with 931,515 participants) were identified for analysis. Family history of CRC in FDRs was associated with increased risk of adenoma (pooled odds ratio [OR] 1.67, 95% confidence interval [CI] 1.46-1.91), NAA (pooled OR 1.35, 95% CI 1.21-1.51), AA (pooled OR 1.66, 95% CI 1.46-1.88), and AN (pooled OR 1.58, 95% CI 1.44-1.73). The positive associations persisted in all examined subgroups. The risk of adenoma (pooled OR 4.18, 95% CI 1.76-9.91), AA (pooled OR 2.42, 95% CI 1.72-3.40), and AN (pooled OR 2.00, 95% CI 1.68-2.38) was more evident among individuals with 2 or more affected FDRs.

Discussion: Family history of CRC is associated with increased risk of adenoma, NAA, AA, and AN totally, and in all available subgroups. The findings further strengthen the necessity and importance of an intensified screening strategy for individuals with a positive family history of CRC, which is very useful for related health resource allocation and policymaking.