New study provides critical insights into the factors that influence a patient’s decision to undergo genetic testing for breast cancer susceptibility genes and will help guide future efforts to improve equitable access to genetic testing
Women newly diagnosed with breast cancer who declined genetic testing were more likely to be older and have no family history of cancer, according to a new cross-sectional study from the Lady Davis Institute for Medical Research (LDI) and McGill University. Researchers found no differences in testing uptake based on ancestry, race, or ethnicity, suggesting that women who chose not to undergo testing may have correctly perceived themselves to be at lower risk of carrying a high-risk inherited cancer variant.
The study, published in JAMA Network Open, examined factors associated with genetic testing uptake among women offered free genetic counseling and testing through a publicly funded healthcare setting. While previous findings from the same cohort showed that more than 90% of eligible patients accepted testing, the new analysis focused on the small proportion who declined and sought to understand why.
Among 805 eligible women diagnosed with invasive breast cancer, 90.6% underwent genetic testing. Women who declined were more likely to be older and to report no family history of cancer. Family history, age, and stage at diagnosis were independently associated with testing uptake. In contrast, ancestry and race or ethnicity were not associated with the decision to accept or decline testing.
“Genetic testing can provide information that helps guide treatment decisions and identify risks for family members. It is particularly important because identifying a pathogenic variant can directly inform surgical and systemic therapy decisions for the 5-10% of patients who test positive,” said Dr. Stephanie M. Wong, Principal Investigator at the LDI, Surgical Oncologist and Director of the Stroll Cancer Prevention Centre High Risk Breast Clinic at the Jewish General Hospital University Health Centre, Associate Professor in the Departments of surgery and Oncology at McGill University and lead author of the study. “What stood out in our analysis was that ancestry did not influence testing decisions. Instead, women who declined testing were more often those with characteristics associated with a lower likelihood of carrying a high-risk inherited variant.”
The findings differ from some previous reports suggesting disparities in genetic testing across racial and ethnic groups. The authors point out that universal access within a single-payer healthcare system where cost is not a deciding factor may help reduce barriers that contribute to such differences elsewhere.
“Our study demonstrates that when genetic testing is offered universally and without financial burden, uptake is high across diverse populations,” said William Foulkes, co-senior author of the study and Distinguished James McGill Professor in McGill University’s Departments of Medicine, Oncology, and Human Genetics as well as Senior Investigator and Head of the Cancer Genetics Laboratory at the LDI. “The key finding is not that uptake exceeds 90%, which was already known, but that the women who declined testing were not distinguished by ancestry. Rather, many appeared to accurately assess that their chances of carrying a high-risk variant were relatively low.”
In conclusion, this research provides compelling evidence that removing financial barriers and integrating genetic counseling and testing into standard oncology care can lead to more equitable access to potentially life-saving information. It underscores the need for health systems worldwide to evaluate how their policies impact the utilization of genetic testing.
Totten SP, Rezoug Z, Atayan A, Foulkes WD, Wong SM. Genetic Testing Uptake Among Patients With Newly Diagnosed Breast Cancer. JAMA Netw Open. 2026;9(9):e2632279. Doi:10.1001/jamanetworkopen.2026.32279.