Hereditary breast cancer genetic testing: a step-by-step guide
NCCN hereditary cancer testing criteria include breast cancer diagnosed at age 50 or younger, triple-negative breast cancer, male breast cancer, ovarian or pancreatic cancer, high-risk prostate cancer, and Ashkenazi Jewish ancestry.
If one of these applies to you or a close relative, ask your clinician for a hereditary cancer risk assessment. A family history that sounds reassuring at first glance can still contain a pattern that changes your screening plan.
The hereditary breast cancer genetic testing process has several decision points: who to test first, which genes to include, how to interpret an uncertain or negative result, and what to do next. A result is useful only when it is read alongside your personal and family history. Use the steps below to move from a risk clue to a plan you can act on.
1. Identify the family-history clues that warrant assessment
Around 5% to 10% of breast cancer cases are hereditary. Pathogenic variants in BRCA1 and BRCA2 account for up to half of hereditary breast cancer cases. Those figures put inherited risk in perspective: it affects a minority of cases, but identifying it can change surveillance and care for you and relatives.
Start with diagnoses in your biological family, on both your mother’s and father’s sides. Record the cancer type, the relative’s relationship to you, and age at diagnosis if known. Note relatives who have had breast, ovarian, pancreatic, or high-risk prostate cancer. Include male breast cancer and Ashkenazi Jewish ancestry in the history you share with your clinician.
Clinical criteria are signals to assess risk, not a diagnosis. A single item may prompt a discussion; several cancers on one side of the family, especially at younger ages, may make the pattern more informative. If details are missing, say so. Do not guess at a relative’s diagnosis or age just to complete a form.
| Family-history or personal-history clue | Action to request |
|---|---|
| Breast cancer diagnosed at age 50 or younger | Ask whether you meet clinical criteria for hereditary cancer testing |
| Triple-negative breast cancer | Request a risk assessment and discussion of genetic testing |
| Male breast cancer in the family | Include it in the pedigree and ask whether testing is indicated |
| Ovarian or pancreatic cancer, or high-risk prostate cancer | Share the diagnosis and the affected relative’s age if available |
| Ashkenazi Jewish ancestry | Tell the clinician, even if you do not know of a cancer diagnosis in the family |
| A relative has a known pathogenic variant | Ask whether targeted testing for that specific variant is appropriate |
The American Society of Breast Surgeons recommends making genetic testing available to all patients with a personal history of breast cancer. If you have had breast cancer, ask your treating team to review testing even if no one else in your family is known to have had cancer. Your history may qualify you independently of a clear family pattern.
2. Choose the most informative person to test first
If a relative with cancer is available and willing, testing that person first usually provides more informative results than testing an unaffected family member. Their result can show whether a particular inherited variant is present in the family. If you test first and receive a negative result, the answer may be harder to interpret: the family could still have an inherited risk that your test did not identify.
Ask your clinician or genetic counselor to map which relative would be most informative. That may be someone with a relevant cancer diagnosis, especially if they meet testing criteria. If that person has died, cannot access testing, or declines, explain the situation. Testing you may still be reasonable, but the limits of interpreting a negative result need to be clear before you provide a sample.
Bring whatever family information you can gather, but do not delay an appointment because your family record is incomplete. A short list of known diagnoses and approximate ages is more useful than waiting indefinitely for perfect documentation. If you can, verify details with relatives or available medical records, while keeping in mind that access to records varies.
When an affected relative can be tested first, their result often gives the family a clearer starting point.
3. Use pre-test counseling to set the question
Genetic counseling for cancer risk should clarify why testing is being offered, what kind of result the test can return, and how each result could affect care. It also gives you space to discuss privacy, family communication, and the possible emotional impact of learning about inherited risk. You can ask for counseling before testing, whether it is provided by a genetic counselor or another qualified clinician.
Before the appointment, write down the cancers and ages you know about. Then ask:
- Which feature of my history meets the clinical criteria for genetic testing?
- Is an affected relative available to test first?
- Would a targeted test answer the question, or do you recommend a multi-gene panel?
- Which genes are included, and how could a finding change my screening or treatment?
- What would a negative result mean given my family history?
- How will the result be shared, and who can help me explain it to relatives?
A clinician should explain that a test can return a pathogenic variant, a negative result, or a variant of uncertain significance. These outcomes do not carry the same meaning. Ask how the laboratory and your care team handle uncertain findings, and whether you will have a follow-up visit to review the report.
If the test could affect decisions about breast imaging, risk-reducing medication, surgery, or care for relatives, ask who will coordinate those next steps. A result without a follow-up plan can leave you with a report but no clear route through the healthcare system.
4. Match the test to the clinical question
Hereditary cancer testing commonly uses a blood or saliva sample. A laboratory may test one gene or use a multi-gene panel. BRCA1 and BRCA2 are central to hereditary breast cancer assessment, but they are not the only genes associated with inherited susceptibility. Panels may also include genes such as ATM, PALB2, CHEK2, TP53, PTEN, CDH1, and others, depending on the clinical question and the laboratory’s panel.
A broader panel can identify variants beyond BRCA1 and BRCA2, but more genes can also mean more findings that are difficult to interpret or that require gene-specific follow-up. Ask the clinician to connect the proposed panel to your history. The goal is a test that addresses a defined risk question, with a plan for interpreting and acting on the findings.
| Testing approach | What it can clarify | What to ask before proceeding |
|---|---|---|
| Testing for a known family variant | Whether you carry the specific variant already identified in a relative | Is this a targeted test for the exact variant in the family report? |
| BRCA1 and BRCA2 testing | Whether a pathogenic variant is identified in either gene | Does my history support testing these genes alone or a wider panel? |
| Multi-gene panel | Whether a pathogenic variant is found in several genes linked to cancer susceptibility | Which genes are included, and what follow-up applies to each possible finding? |
If a relative’s report identifies a specific variant, bring a copy or ask how the testing service can obtain it. Names of genes alone may not be enough to ensure that the laboratory is testing for the same variant. Verify the details before the sample is collected.
5. Read the result in the context of your history
Interpreting hereditary cancer test results requires both the laboratory classification and the clinical picture. A result is generally reported as pathogenic or likely pathogenic, negative, or a variant of uncertain significance. Ask your clinician to explain the exact category on your report and what it changes for you.
A pathogenic or likely pathogenic finding can guide targeted surveillance and risk-management discussions. The next step depends on the gene, your personal medical history, and your preferences. It may include a more individualized breast-screening plan, discussion of preventive options, or referral to a specialist. A BRCA result does not automatically dictate a single choice; request a conversation about benefits, limitations, timing, and how each option fits your circumstances.
A negative result is not a guarantee that you will never develop breast cancer. If no family variant was known before testing, a negative result may not explain the cancer pattern in your family. Your clinician should assess your remaining risk using your personal and family history and determine whether screening should continue at an increased level.
A variant of uncertain significance means the available evidence does not establish whether that genetic change increases cancer risk. Do not make irreversible medical decisions based only on an uncertain finding. Ask how the result will be reviewed over time and what screening plan follows from your history while the variant remains uncertain.
If your result is positive, ask whether relatives could benefit from targeted testing. Share the report through the clinical team when possible, especially if it contains a specific variant that relatives can use to request testing. A family member who tests negative for a known variant may receive a different interpretation from someone whose family has never had an identified variant.
6. Turn the report into a surveillance plan
The result should lead to a documented plan, not a vague instruction to follow up. Ask who will manage your breast screening, when the next appointment should happen, and whether the plan depends on a particular gene or on your family history. If you already see a primary-care clinician, gynecologist, breast specialist, or oncologist, confirm who owns each part of follow-up.
If a pathogenic variant is identified, discuss gene-specific surveillance with a clinician familiar with hereditary cancer risk. Ask whether your plan includes additional imaging, when it begins, and how results will be coordinated across providers. If the report is negative or uncertain, request the screening recommendation in writing as well. The absence of an actionable variant does not erase the information in your family history.
Preventive options after a positive BRCA test may include intensified surveillance and discussions of risk-reducing medication or surgery, depending on the individual clinical situation. These choices require individualized counseling. Ask for the expected benefit, potential harms, timing, and alternatives before making a decision. You can request a second opinion from a specialist in hereditary breast and ovarian cancer risk if the recommendations are unclear or feel rushed.
Use this short checklist at your appointment:
- Bring a family history with cancer types, relatives, and ages at diagnosis when known.
- Ask which clinical criteria support testing in your case.
- Ask whether an affected relative should be tested first.
- Confirm the test type, genes included, and possible result categories.
- Request a follow-up appointment to interpret the report.
- Leave with a written screening plan and the name of the clinician responsible for coordinating it.
If you need a simple opening line, say: “I’m concerned about inherited cancer risk because of my personal or family history. Can we review whether I meet clinical criteria, who should be tested first, and what follow-up would depend on the result?”
The most useful test is the one tied to a clear clinical question and a follow-up plan. Bring the family history you have, request counseling before testing, and make sure someone interprets the result with you. That sequence helps turn genetic information into decisions you can use.