Genetic Testing — When Is It Needed?

In the vast majority of cases, breast cancer is sporadic, meaning it is not associated with a hereditary predisposition. However, a small percentage — approximately 5-10% — is caused by hereditary gene mutations that significantly increase the risk of developing the disease. For this reason, genetic testing is not intended for all women, but for specific groups with an increased probability of hereditary susceptibility.

The most well-known genes associated with increased risk are BRCA1 and BRCA2. Mutations in these genes are primarily linked to breast and ovarian cancer, while in some cases they may also increase the risk of other malignancies. Today, testing may also include other genes, such as PALB2, CHEK2, and ATM, depending on the family history and clinical characteristics.

The recommendation for genetic testing is made when specific elements raise suspicion of heredity. These include a diagnosis of breast cancer at a young age (typically before 45-50 years), the occurrence of triple-negative breast cancer before the age of 60, the presence of bilateral breast cancer or a combination of breast and ovarian cancer in the same individual, and a strong family history with multiple affected relatives. Male breast cancer in the family, and certain ancestries with a higher carrier frequency such as Ashkenazi Jewish heritage, are also recognized indications. Testing is likewise indicated when a known pathogenic mutation already exists in the family. The evaluation is individualized, following a careful collection and analysis of the family history — often as part of the broader conversation about your personal risk factors.

Genetic testing is performed with a simple blood draw and DNA analysis. However, prior to the test, genetic counseling is essential. Through this process, the actual risk is assessed, the possible results are explained, and misinterpretations that could cause anxiety or lead to incorrect decisions are avoided.

A positive result does not mean that a woman will definitely develop cancer. It means that the risk is elevated compared to the general population. In this case, a more intensive surveillance program may be discussed, often including breast MRI, while in selected cases, risk-reducing surgical options may also be considered. Additionally, when a cancer diagnosis already exists, knowledge of the mutation may influence the therapeutic strategy, enabling more targeted treatment choices.

Appropriately indicated genetic testing can provide invaluable information. It helps in designing the right preventive program, in making treatment decisions, and in informing family members who may also need testing. The decision to undergo testing is always made with medical guidance and not preemptively without a clear indication.

Understanding Your Results

Genetic test results generally fall into three categories. A positive result confirms a pathogenic mutation associated with increased risk; this does not mean cancer is inevitable, but it does call for a personalized plan. A negative result is reassuring, although it does not reduce your risk below that of the general population — routine screening and self-awareness remain just as important. A variant of uncertain significance (VUS) is a genetic change whose meaning is not yet established; it is not acted upon as if it were positive, and many such variants are later reclassified as harmless. Interpreting these results correctly is one of the main reasons genetic counseling is so valuable.

What It Means for Your Family

Because hereditary mutations can be passed from one generation to the next, your result may have implications well beyond yourself. A confirmed mutation means that close blood relatives — children, siblings, parents — each have a meaningful chance of carrying the same change. With your consent, they can be offered their own counseling and testing, allowing those who are affected to begin earlier, more intensive surveillance and those who are not to be reassured. This shared knowledge is one of the most powerful benefits of testing, turning a personal result into protection for the people you love. You can read more about how inherited risk fits into the wider picture on our page about breast cancer.

Knowledge, when used correctly, does not cause fear — it provides control and the ability to act promptly. For trustworthy background information, the U.S. National Cancer Institute offers clear, regularly updated guidance on hereditary breast cancer.

A message for patients: Genetic testing is a tool for prevention and personalization of care — not a reason for worry. Proper evaluation helps us act early and safely.