Universal tumor screening and mainstream genetic testing for Lynch syndrome in colorectal cancer: a scoping review of barriers and facilitators

: Patients with colorectal cancer (CRC) and Lynch syndrome (LS) have elevated cancer risks and require personalized treatment and targeted surveillance. At-risk relatives can also benefit from preventive measures. However, LS remains largely undiagnosed. Integration of universal tumor screening (UTS) with mainstream genetic testing in patients with CRC has been recommended, but implementation of this approach remains inconsistent. This scoping review mapped evidence on barriers and facilitators in diagnostic pathways that integrate UTS and mainstream genetic testing for LS in CRC. A search of MEDLINE, Scopus, CINAHL and PsycINFO was conducted, and five articles were selected. Barriers and facilitators were mapped to the Theoretical Domains Framework (TDF). The most frequently mapped domains were Environmental Context and Resources (in 5/5 articles) Social/Professional Role and Identity, Beliefs about Consequences, Social Influences, and Behavioral Regulation (all in 4/5 articles). Barriers included insufficient clinician education, difficulties in navigating consent processes and interpreting testing results, and perceived lack of evidence demonstrating the benefit of genetic testing. Unclear and conflicting perceptions among different professional groups about who should be responsible for essential components of genetic testing and follow-up also emerged. Social Influences such as strong leadership, collaboration, and networked support from "champions" acted as key facilitators. Mechanisms of Behavioral Regulation, including audit, feedback, and ongoing education, as well as appropriate resourcing, were identified as essential for sustaining practice change. Future studies could usefully explore patients' views and preferences regarding novel diagnostic pathways for LS in CRC that align UTS and mainstream genetic testing, as well as strategies developed and implemented in low-resource settings.