Who this article is for
This article is for you if:
- You have recently been diagnosed with breast cancer.
- You have triple-negative breast cancer.
- You have ovarian cancer.
- You have a strong family history of breast or ovarian cancer.
- You are healthy but are wondering whether genetic testing may help assess your future cancer risk.
- You are seeking a second opinion regarding breast cancer genetics.
Clinical observation
One consultation has stayed with me throughout my career.
A young woman in her thirties attended my clinic after discovering a breast lump only a few weeks earlier. During that short period, the lump had become noticeably larger, firmer, and the skin overlying the breast had started to change.
She was otherwise healthy, hardworking, and had one dream she had never given up on—having children one day.
Her biopsy confirmed triple-negative breast cancer, and the cancer had already spread to nearby lymph nodes.
Triple-negative breast cancer can sometimes grow and spread more quickly than other types of breast cancer. When it presents with a rapidly growing tumour and involved lymph nodes, treatment usually needs to begin promptly.
This was one of the rare consultations that affected me emotionally. As oncologists we remain objective, but we also recognise when a patient’s hopes for the future are suddenly placed in jeopardy.
What surprised me
When I asked about her family history, there was only a relatively limited history of breast cancer in an older maternal relative.
Many people assume that hereditary breast cancer always comes from families with multiple relatives affected by cancer.
That simply is not true.
A blood test showed that she carried an inherited harmful change—called a pathogenic variant—in the BRCA1 gene.
Triple-negative breast cancer is an important reason to consider genetic testing because inherited BRCA1 or BRCA2 changes are found more often in this subtype than in many other breast cancers.
Suddenly, the diagnosis affected not only her treatment, but also her future cancer risks and potentially the health of other family members.
Why genetic testing matters
Genetic testing can affect much more than a patient’s future cancer risk.
It may also change treatment decisions today.
If testing identifies an inherited harmful change in BRCA1 or BRCA2, the result may influence:
- surgical planning
- eligibility for targeted medicines called PARP inhibitors
- screening and prevention of future cancers
- genetic testing and cancer prevention for relatives
Current guidelines recommend BRCA1 and BRCA2 testing for many newly diagnosed patients.
This is particularly important for:
- younger patients
- patients with triple-negative breast cancer
- patients with ovarian cancer
- patients with a concerning personal or family history
- patients who may be eligible for targeted treatment
Australian guidance recommends considering BRCA1, BRCA2 and PALB2 testing for patients with triple-negative breast cancer at any age.
For selected patients with high-risk, HER2-negative early breast cancer and an inherited BRCA1 or BRCA2 change, a targeted tablet called olaparib may reduce the chance of the cancer returning and improve survival.
Immunotherapy is a separate treatment decision.
Many eligible patients with stage II or III triple-negative breast cancer receive chemotherapy together with pembrolizumab before surgery, followed by pembrolizumab after surgery.
This decision is based mainly on the stage and features of the breast cancer—not on the BRCA result alone.
One of the hardest conversations: fertility
This consultation became even more difficult.
She desperately wanted children.
Many patients understandably ask whether treatment can be delayed while eggs or embryos are preserved.
Fertility preservation should be discussed as early as possible—ideally before cancer treatment begins. Patients who are interested or uncertain should be referred urgently to a fertility specialist.
However, rapidly growing cancers may leave very little time.
In her situation, delaying treatment carried genuine risk.
Both she and I understood that beginning treatment promptly offered the best chance of successfully treating her cancer.
That was an incredibly difficult decision.
Even with modern treatment, high-risk triple-negative breast cancer can still return.
However, finding an inherited BRCA1 pathogenic variant may also provide access to additional targeted treatment, such as olaparib, for eligible patients.
The 2025 ASCO fertility guideline recommends discussing reproductive risks at diagnosis and referring patients who are interested in or uncertain about fertility preservation before cancer-directed treatment.
What our Australian research taught us
One of the privileges of my career has been contributing to Australian research into hereditary breast cancer.
In our prospective Australian study published in the Medical Journal of Australia, we offered genetic testing to women with newly diagnosed breast cancer, regardless of age, tumour type or family history.
Among all women who underwent testing, approximately 8%—about 1 in 12—carried an inherited pathogenic variant in a cancer-predisposition gene.
More than half of the women found to carry a pathogenic variant would not have met the Australian testing criteria being used at the time.
Importantly, identifying the genetic result changed the clinical management of most women who carried a pathogenic variant.
This showed us that relying only on a strong family history can miss patients who may benefit from testing.
Many people have small families, limited information about relatives or inherited changes passed through the father’s side of the family.
That is why a careful genetic assessment remains so important.
Can healthy people have genetic testing before cancer develops?
One of the most encouraging changes I have seen over the past decade is the increasing number of Australians seeking genetic assessment before they develop cancer.
This represents a remarkable shift.
More general practitioners are discussing hereditary cancer risk.
More families are asking the right questions.
More individuals are identifying inherited cancer risk before cancer develops.
As both a medical oncologist and cancer genetics physician, this is exactly where I hope Australian healthcare continues to move—towards prevention rather than reaction.
My clinical perspective
What has surprised me most over the past ten years is not the increasing availability of genetic testing.
It is the increasing awareness among patients.
More Australians are proactively asking whether they carry an inherited cancer gene before they ever develop breast or ovarian cancer.
That is a major step forward.
Unfortunately, this is still not the reality in many neighbouring countries.
In my international second-opinion practice, I still meet patients from Sri Lanka, Indonesia, the Philippines and the Maldives who have not been offered inherited genetic testing, even when their diagnosis suggests that testing may be appropriate.
In some regions, access to accredited laboratories and specialist cancer genetics services can also be limited.
High-quality testing performed through accredited laboratories remains essential for accurate diagnosis and treatment planning.
Key takeaways
- A strong family history is not always present
Inherited cancer-predisposition variants can be found even when few or no relatives are known to have had cancer. - Genetic testing can change treatment and prevention
A BRCA1 or BRCA2 result may affect targeted-treatment eligibility, surgical planning and future cancer-risk management. - The result can also help the wider family
Relatives may be able to undergo targeted testing and access earlier screening or preventive care.
Key evidence
- Bedrosian I, Somerfield MR, Achatz MI, et al. Germline testing in patients with breast cancer: ASCO–Society of Surgical Oncology guideline. J Clin Oncol. 2024;42(5):584-604. doi:10.1200/JCO.23.02225
- Cancer Institute NSW. BRCA1, BRCA2 and PALB2—genetic testing. eviQ. Protocol 620, version 16. Last reviewed October 29, 2025. Accessed July 18, 2026. https://www.eviq.org.au/cancer-genetics/adult/genetic-testing-for-heritable-pathogenic-variants/620-brca1-brca2-and-palb2-genetic-testing
- Schmid P, Cortes J, Dent R, et al. Overall survival with pembrolizumab in early-stage triple-negative breast cancer. N Engl J Med. 2024;391(21):1981-1991. doi:10.1056/NEJMoa2409932
- Geyer CE Jr, Garber JE, Gelber RD, et al. Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high-risk, early breast cancer. Ann Oncol. 2022;33(12):1250-1268. doi:10.1016/j.annonc.2022.09.159
- De Silva DL, Stafford L, Skandarajah AR, et al. Universal genetic testing for women with newly diagnosed breast cancer in the context of multidisciplinary team care. Med J Aust. 2023;218(8):368-373. doi:10.5694/mja2.51906
- Su HI, Lacchetti C, Letourneau J, et al. Fertility preservation in people with cancer: ASCO guideline update. J Clin Oncol. 2025;43(12):1488-1515. doi:10.1200/JCO-24-02782
Frequently asked questions (FAQs)
- Should Every Patient With Breast Cancer Have Genetic Testing?
Testing recommendations are becoming broader. Many newly diagnosed patients should now be offered BRCA1 and BRCA2 testing, particularly younger patients, those with triple-negative breast cancer and those who may qualify for targeted treatment. The decision should consider the patient’s age, cancer type, personal history and family history.
- Does Having a BRCA Mutation Mean I Will Definitely Develop Cancer?
No. A BRCA pathogenic variant substantially increases cancer risk, but cancer is not inevitable.
- Can I Carry a BRCA Mutation if Nobody in My Family Has Breast Cancer?
Yes. Small families, incomplete information, inheritance through the father’s side and relatives who carry the variant without developing cancer can all hide an inherited pattern.
- Can Genetic Testing Change My Treatment?
Yes. A BRCA1 or BRCA2 result may influence eligibility for PARP inhibitors, surgical planning and future cancer-prevention strategies.
Dr Dilanka De Silva
MBBS, MRCP(UK), MRCP(UK SCE Oncology), FRACP, PhD
Medical Oncologist & Cancer Genetics Physician
Memorial Sloan Kettering Cancer Center Fellow (New York, USA)