For a small but important proportion of women and men, breast cancer risk is significantly elevated because of an inherited mutation in a high-risk gene. Identifying whether such a mutation is present has profound implications — for the individual's own risk management, for the surgical and treatment decisions they face, and for the health of their blood relatives.

Genetic testing is not appropriate for everyone with a family history of breast cancer, and it is most informative and most impactful when it is directed by a thorough clinical assessment of who is most likely to benefit. At Breast & Surgical Oncology at The Poche Centre, identifying patients who warrant genetic assessment, ordering genetic testing and/or coordinating timely referral to the appropriate specialists is an integral part of how we manage breast cancer risk.

When Is Genetic Testing Indicated?

Genetic testing is recommended when the personal or family history raises a meaningful likelihood of an inherited gene mutation. Features that increase this likelihood include the following.

Multiple relatives on the same side of the family affected by breast or ovarian cancer, particularly when diagnosed at a young age. Breast cancer diagnosed before age 40 in any first or second-degree relative. A family member with both breast and ovarian cancer, or bilateral breast cancer. A male relative diagnosed with breast cancer. Known BRCA1, BRCA2, or other high-risk gene mutation in the family. Ashkenazi Jewish ancestry, where BRCA mutations occur at a higher population frequency. A personal diagnosis of triple-negative breast cancer, particularly before age 60. A personal diagnosis of breast cancer with a significant family history.

At your consultation, your surgeon will assess your history against these and other criteria and advise whether genetic testing is likely to be informative and appropriate for your situation.

The Genetic Testing Process

Genetic testing for inherited breast cancer risk can now be organised by specialists as well as clinical geneticists.  This has made genetic testing more accessible,  as public genetic clinics services are in high demand and often have long waiting lists.    Genetic testing involves genetic counselling, identification who should be tested, making a referral for the test (which is a blood test) and delivering their results.  For those patients who are identified as having a gene or genetic variant of uncertain significance, or those patients who benefit from more in depth genetic information then referral to a familial cancer centre or private genetic specialist will be made.

Genetic counselling involves a detailed structured assessment of your family history, an explanation of what genetic testing can and cannot tell you, an honest discussion of the emotional and practical implications of a positive, negative, or inconclusive result, and — where testing proceeds — the collection of a blood or saliva sample for laboratory analysis.

The index case — genetic testing is most informative when the first person tested in a family is someone who has actually been diagnosed with cancer (the index case), as they are most likely to carry a detectable mutation if one exists in the family. Testing an unaffected relative when no affected family member has been tested may return a negative result that is difficult to interpret. Where an affected family member is available and willing, testing them first is strongly preferred.

Testing panels — modern genetic testing analyses multiple genes simultaneously using next-generation sequencing technology, providing a comprehensive assessment of inherited risk across all clinically relevant genes in a single test. Genes routinely assessed include BRCA1, BRCA2, PALB2, CHEK2, ATM, CDH1, PTEN, and others depending on the clinical indication and the laboratory panel used.

Turnaround time — results from comprehensive gene panel testing typically take four to eight weeks from the time of sample collection.

Possible Results and What They Mean

Pathogenic mutation identified — a disease-causing mutation has been found in one of the tested genes. This result significantly elevates the estimated lifetime breast cancer risk and has direct implications for screening, surveillance, risk-reducing surgery, and systemic treatment where relevant. It also means that blood relatives have a 50% chance of carrying the same mutation and should be offered targeted testing.

Variant of uncertain significance (VUS) — a genetic change has been identified, but current evidence is insufficient to determine whether it increases cancer risk. VUS results do not change clinical management and should not be used to make decisions about screening or surgery. The classification of a VUS may change over time as more evidence accumulates, and patients are typically notified if a reclassification occurs.

No pathogenic variant identified (negative result) — no disease-causing mutation has been found in the genes tested. In a family where an affected relative tested positive for a specific mutation, a negative result in an unaffected relative is genuinely reassuring and returns that person's risk to close to the population average. In a family where no affected relative has been tested, a negative result is less informative — the absence of a detectable mutation does not mean no inherited risk exists, as not all familial risk is explained by currently tested genes.

Implications for Family Members

A positive genetic test result has implications that extend well beyond the individual being tested. Each first-degree relative (parent, sibling, or child) of a mutation carrier has a 50% chance of carrying the same mutation, regardless of sex. This means that sons and daughters, brothers and sisters, and parents of a mutation carrier all have a meaningful personal interest in knowing the test result.

Sharing genetic information with family members is encouraged but is ultimately a personal decision. Genetic counsellors can provide guidance and written resources to assist patients in communicating their results to relatives, and can in some circumstances assist with family notification.

For male relatives who carry a BRCA2 mutation in particular, the implications include elevated risks of breast, prostate, and pancreatic cancer that warrant their own specialist assessment and surveillance planning.

After Genetic Testing

For patients in whom a pathogenic mutation is confirmed, a comprehensive risk management plan is developed in collaboration with the multidisciplinary team. This plan addresses personalised screening and surveillance, chemoprevention options where appropriate, and surgical risk-reduction options including risk-reducing mastectomy and salpingo-oophorectomy for BRCA carriers. These decisions are always made at the patient's own pace, with full information and without pressure.

For patients in whom testing is negative or returns a VUS, risk management is guided by the clinical and family history rather than the genetic result, and appropriate screening continues based on the estimated level of familial risk.

Booking an Appointment

If you are concerned about your family history of breast cancer and would like specialist assessment of whether genetic testing is appropriate for you, a GP referral to our practice is the first step. We will assess your history at consultation and refer you to the most appropriate familial cancer service or clinical geneticist where indicated.

This page is intended as a general guide only and does not replace personalised medical advice. Genetic testing decisions are complex and deeply personal, and should always be made in the context of formal genetic counselling.