As early as 2026, a new method involving saliva and blood tests could transform the way breast cancer risk is assessed, leading to more personalized clinical care. Researchers are excited about this advancement, which could significantly enhance current screening practices. Dr. Mathias Cavaillé, a clinical physician and researcher at CHU de Québec – Université Laval Research Centre, is leading a project aimed at integrating a tool known as the polygenic risk score (PRS) into breast cancer screening protocols. This development promises to refine risk assessment and improve early detection strategies.
The Polygenic Risk Score: A Revolutionary Tool in Breast Cancer Screening
The polygenic risk score is a cutting-edge tool that assesses the likelihood of developing breast cancer based on an individual’s genetic makeup. It works by analyzing 313 genetic variations associated with the disease. While each variation on its own may pose a low risk, when combined, they can significantly increase a person’s risk of developing breast cancer.
The PRS offers a more refined and personalized approach to breast cancer screening. For women at moderate genetic or familial risk, the traditional approach has been to manage all patients in the same way. This often involves annual or biennial mammography screenings beginning at age 40. However, with the introduction of PRS, a more nuanced risk assessment can be made, allowing for tailored screening strategies that better match a woman’s risk profile.
Personalizing Breast Cancer Screening Based on Risk Levels
A key aspect of this new approach is recognizing that not all women at moderate risk have the same likelihood of developing breast cancer. According to Dr. Cavaillé, the lifetime breast cancer risk for women considered at moderate risk is about 20%, which is double that of the general population. However, the risk level among these women varies widely: half may be at low risk while the other half may be at a much higher risk level. This means that while 25% of women considered at moderate risk may have a risk comparable to that of the general population, another 25% may have a risk as high as those with BRCA1 or BRCA2 mutations. The ability to accurately identify these differences allows for more precise and individualized management.
With personalized screening protocols, women at low risk could begin mammography screenings later, perhaps at age 50, while women at higher risk could start screenings much earlier—at age 30 or 35—and could undergo more frequent screenings using mammography and magnetic resonance imaging (MRI). In some cases, preventive surgery could even be considered for those at extremely high risk.
Combining Genetics with Clinical Practice
Genetic mutations in high-risk genes like BRCA1 and BRCA2 are well-known for significantly increasing the chances of developing breast cancer. However, the polygenic risk score includes genetic variations beyond these high-risk mutations, such as more common gene variations that can still play a role in breast cancer susceptibility. These variations may not be enough on their own to raise alarm, but when considered collectively, they can provide important insight into a patient’s overall risk.
One of the significant challenges in current breast cancer care is the management of women who have a family history of the disease but do not carry any of the known mutations in breast cancer predisposition genes. The PRS provides a valuable solution for this group, offering a more accurate method of identifying those who may be at a higher risk, even when genetic testing for the BRCA mutations comes back negative.
Conclusion
The ongoing research is funded by Génome Québec, the Fondation cancer du sein de Québec, and the Fondation du CHU de Québec. If successful, the polygenic risk score will be incorporated into clinical practice as a vital tool for improving breast cancer screening protocols. This will not only lead to more personalized care but will also help to identify at-risk individuals earlier, ultimately saving lives and improving outcomes.
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