Advancing Germline Genetic Testing for Breast Cancer in Resource-Restricted Settings: Evidence, Barriers, and a Practical Roadmap for Implementation.

Germline genetic testing (GGT) is increasingly integrated in breast cancer management, yet its implementation, particularly in resource-restricted settings, remains a challenge. This narrative review addresses current evidence and international guideline recommendations regarding GGT in breast cancer, with emphasis on clinical utility, evolving testing criteria and implementation challenges, drawing partly on the experience and demographic characteristics of Jordan as an example of a resource-restricted setting. Approximately 10% of patients with breast cancer carry germline pathogenic variants, mostly involving BRCA1 and BRCA2. GGT guides systemic therapy including PARP inhibitors, informs surgical decisions and enables cascade testing for at-risk relatives to support prevention and early detection. Recent guideline updates from major international societies have expanded eligibility, with recommendations supporting testing up to age 65 and some advocating universal testing. In low- and middle-income countries, these expanded criteria render a large proportion of patients eligible but raise concerns regarding infrastructure, cost and variant of uncertain significance (VUS) interpretation. While expanded testing increases detection of actionable variants and may improve outcomes, universal GGT remains controversial, and context-adapted strategies are required to balance benefit, feasibility, and sustainability. Overall, integrating GGT into routine breast cancer care represents a key component of precision oncology and hereditary cancer prevention strategies worldwide, especially in early-onset disease populations. Implementation requires multidisciplinary coordination and equitable access to testing services.