Call for Action: Expanding Global Access to Hereditary Cancer Genetic Testing
Published:09 Oct.2022 Source:The LANCET Oncology
Globally, access to hereditary cancer genetic testing (CGT) remains inadequate, despite the important implications for clinical care when a pathogenic variant is identified. The disparity in access to testing is particularly evident in low-income and middle-income countries (LMICs), where CGT is often unavailable or prohibitively expensive, especially in public health systems. Even when testing is affordable to patients, logistical barriers further restrict access because patients assume indirect costs.
In high-income countries, a deficient capacity for CGT has prompted a study on forgoing counselling before testing. This approach harnesses technology, instead of one-to-one counselling, for genetics education, allowing high throughput of patients while maintaining autonomy and informed choice, and could be used in LMICs. There is a clinical imperative to expand access to CGT for patients with breast cancer (primarily stages II-IV) or ovarian cancer, and to increase the capacity for targeted therapy for patients with pathogenic variants in BRCA1 or BRCA2. We argue that the barriers to testing in LMICs are surmountable, but that foundational work to enhance access to CGT is urgently needed.
Since the discovery of hereditary cancer genes in the 1990s, guidelines for germline testing have evolved from testing patients with specific cancer subtypes, a family history of cancer, Ashkenazi Jewish ancestry, or a young age at diagnosis to including patients who might benefit from targeted therapy. However, contemporary evidence indicates that patients with Caribbean (specifically Bahamian), Latinx, Middle Eastern, and Indian ancestry have rates of pathogenic variants in BRCA1 and BRCA2 (appendix pp 2-4) similar to those with Ashkenazi Jewish ancestry.
Additionally, identification of a pathogenic variant in a patient with cancer can prompt germline CGT in family members, known as cascade testing, which has been proposed as an effective alternative to population screening.7 Family members with the same pathogenic variant could qualify for enhanced screening and risk reduction. Upfront investments in systems for CGT will contribute to health-care savings within LMICs through the potential for early detection and prevention.
In sum, we call for expanded access to CGT, especially for patients diagnosed with breast or ovarian cancer, and for testing to not be restricted by ancestry. Country-specific guidelines are needed to establish which patients with cancer qualify for CGT, considering local resources, and we favour models that emphasise specific cancer diagnosis because the identification of a pathogenic variant has implications for cancer treatment. This approach could avert the need to ascertain, before testing, if an individual meets prescriptive ancestry, family-history, or age criteria.