Family History and Genetic Testing
Family History of Breast Cancer
Breast cancer is one of the most common cancers to affect Australian women, with 1 in 8 women having a diagnosis of breast cancer by 85 years of age.
Because the disease is so common, many people have someone in their family who has had a diagnosis of breast cancer.
Rarely, breast cancer can develop as a result of a faulty gene which is inherited from one generation to the next. This accounts for 5% of breast cancer cases.
The inheritance of a faulty gene can occur through a mother’s or father’s lineage. Occasionally a person may be the first in their family to have a faulty gene.
Such genes may be associated with other types of cancer, particularly ovarian cancer and cancer of the fallopian tube.
There are particular aspects of a person’s history which increases the suspicion there may be an inherited faulty gene at fault for a breast cancer including:
A strong family history
Multiple relatives on the same side of the family with breast and/or ovarian cancer
Breast cancer diagnosed in a young woman
Men in the family with a breast cancer diagnosis
Breast cancer in both breasts
Particular types of breast cancers, namely the ‘triple negative’ subtype
Families with Ashkenazi Jewish heritage
Understanding Your Breast Cancer Risk
95% of women are at average or population risk of developing breast cancer.
4% are at ‘moderate risk’ of developing breast cancer.
1% is at high risk of developing breast cancer.
In addition to family history, there are several online risk calculators you can use to calculate which risk category you fall into, what your breast screening regime should be and what steps you can take to decrease your breast cancer risk.
These include:
Risk calculator tool developed by the Peter McCallum Cancer Centre, Melbourne.
iBIS risk calculator tool.
Family History Definitions
First degree relatives are brothers and sisters, children and parents.
Second degree relatives include aunts, uncles, grandparents, nieces and nephews.
Breast Cancer Risk Categories
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At or slightly above population risk.
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Moderate risk of developing breast cancer.
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High risk of developing breast cancer.
Recommendations for breast cancer screening will depend on which risk category a woman falls into.
Regardless, all women are recommended to be ‘breast aware’ and to perform breast self-examinations regularly, see a doctor immediately to report any new symptoms and have a screening mammogram every 2 years from the age of 40-50.
Genetic Testing for Breast Cancer
In some cases, breast cancer is linked to specific inherited genetic faults.
The most well-known mutations are in the BRCA1 and BRCA2 genes, which significantly increase the risk of breast and ovarian cancers.
Genetic testing can help identify if you carry these or other mutations linked to breast cancer.
Testing is only done under the supervision of a specialist as there are pros and cons to testing and these need to be discussed prior to testing.
What Does Genetic Testing Involve?
Consultation
First, you will meet with a genetic counselor or specialist to discuss your family history and the potential risks and benefits of genetic testing.
Testing
The actual test is usually done through a blood or saliva sample, which will be analyzed in a laboratory to check for mutations.
Results and Counseling
Once you receive your results, a genetic counselor will explain what they mean for your personal risk and your family’s risk.
Depending on the findings, your doctor may recommend enhanced screening or preventive measures.
Benefits of Genetic Testing
Personalized Risk Assessment
Knowing your genetic status can help your doctor tailor a screening plan, which may include starting mammograms or MRIs at an earlier age or more frequent screenings.
Informed Decision-Making
If a genetic mutation is found, you can consider preventive measures such as enhanced screening, medication, or even surgery (such as prophylactic mastectomy).
Family Awareness
Your results can provide valuable information for other family members who may also benefit from genetic testing or closer monitoring.
Considerations and Limitations
Genetic Testing Does Not Guarantee Prevention
Genetic testing doesn't guarantee a cancer diagnosis or prevention; it only assesses risk.
Emotional and Financial Considerations
Testing may have emotional and financial implications, and health insurance coverage for testing can vary.
A Negative Result Does Not Eliminate Risk
A negative test result doesn’t eliminate your risk of breast cancer, especially if there is a significant family history.
Other factors like lifestyle, environment, and non-genetic risk factors also play a role.
Next Steps
If you are concerned about your breast cancer risk due to family history, speak with your healthcare provider or a genetic counsellor to discuss whether genetic testing is right for you.
Based on the results, your care team can help develop a personalized risk management plan that may include early detection strategies, lifestyle changes, or preventive treatments.
Questions for Your Healthcare Provider
You may wish to ask your healthcare provider or genetic counsellor:
Does my family history increase my risk of breast cancer?
Which breast cancer risk category do I fall into?
Should I consider genetic testing?
What are the potential benefits and limitations of genetic testing?
How could the results affect my breast screening?
What preventive measures may be available if a genetic mutation is found?
Frequently Asked Questions
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Breast cancer is one of the most common cancers to affect Australian women, with 1 in 8 women having a diagnosis of breast cancer by 85 years of age.
-
Rarely, breast cancer can develop as a result of a faulty gene which is inherited from one generation to the next.
This accounts for 5% of breast cancer cases.
-
Yes. The inheritance of a faulty gene can occur through a mother’s or father’s lineage.
-
These include a strong family history, multiple relatives on the same side of the family with breast and/or ovarian cancer, breast cancer diagnosed in a young woman, men in the family with a breast cancer diagnosis, breast cancer in both breasts, triple-negative breast cancer and families with Ashkenazi Jewish heritage.
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The categories are:
Category 1: At or slightly above population risk
Category 2: Moderate risk
Category 3: High risk
95% of women are at average or population risk, 4% are at moderate risk and 1% is at high risk of developing breast cancer.
-
Genetic testing can identify specific inherited genetic faults linked to breast cancer.
The most well-known mutations are in the BRCA1 and BRCA2 genes, which significantly increase the risk of breast and ovarian cancers.
-
The actual test is usually done through a blood or saliva sample, which will be analyzed in a laboratory to check for mutations.
-
A genetic counselor will explain what your results mean for your personal risk and your family’s risk.
Depending on the findings, your doctor may recommend enhanced screening or preventive measures.
-
Genetic testing can help with personalized risk assessment, informed decision-making and providing valuable information for other family members who may also benefit from genetic testing or closer monitoring.
-
No.
A negative test result doesn’t eliminate your risk of breast cancer, especially if there is a significant family history.
Other factors like lifestyle, environment, and non-genetic risk factors also play a role.
-
Speak with your healthcare provider or a genetic counsellor to discuss whether genetic testing is right for you.
Based on the results, your care team can help develop a personalized risk management plan.
Helpful Resources
Need Further Advice?
Family history is important in assessing breast cancer risk.
Genetic testing can identify inherited mutations linked to breast cancer, although these genetic faults are rare.
If you have further questions or would like to explore genetic testing, please schedule an appointment with your healthcare provider.