Your personal and family history can provide important clues about inherited cancer risk. Genetic counseling and testing can help determine whether an inherited genetic change may be contributing to that risk and, when appropriate, help guide screening, risk-reduction strategies and care for you and potentially your family.
Understanding Cancer and Inherited Risk
Cancer develops because of genetic changes that affect how cells grow and function, but most of these changes are acquired during a person’s lifetime and are not inherited. Some people, however, inherit a genetic change that increases their likelihood of developing breast cancer or certain other cancers.
Inherited cancer risk can come from either your mother’s or your father’s side of the family. Looking at patterns of cancer across several generations can help your care team determine whether genetic counseling or testing may provide useful information. Genetic testing is now recommended for many people diagnosed with breast cancer, including some who may not have a strong family history.
When Might Genetic Counseling Be Helpful?
You do not need to know whether cancer in your family is hereditary before meeting with your care team. Genetic counseling can help identify patterns that may suggest inherited risk and determine whether testing could provide information useful to you or your relatives.
Factors that may prompt a closer look at hereditary cancer risk include:
- Breast cancer diagnosed at a younger age
- More than one primary cancer in the same person
- Several relatives with breast cancer or related cancers
- A family history of ovarian, pancreatic, male breast or certain prostate cancers
- A known inherited cancer-related genetic variant in the family
- Certain ancestry associated with a higher prevalence of particular inherited genetic variants
These factors do not necessarily mean that an inherited genetic change is present, and the absence of these patterns does not always mean genetic testing is unnecessary. Your personal diagnosis, family history and other clinical information can be considered together when determining whether genetic counseling or testing is appropriate.
What Does Genetic Testing Look For?
Genetic testing typically uses a blood or saliva sample to look for inherited changes in genes associated with cancer risk. BRCA1 and BRCA2 are among the best-known genes associated with inherited breast and ovarian cancer risk, but they are not the only genes that can affect breast cancer risk.
When appropriate, multigene panel testing can evaluate several genes at the same time, including genes such as PALB2, CHEK2 and ATM. The genes included in testing can depend on your personal and family history, whether you have already been diagnosed with cancer and what information may be useful for your care.
Finding an inherited genetic change does not mean that cancer will definitely develop. Instead, the result can provide additional information about risk that your care team can consider along with your health history, family history and other clinical factors.
What Can Genetic Test Results Tell You?
Genetic test results are not simply a yes-or-no answer about whether you will develop cancer. The meaning of a result depends on what was found, why testing was performed, and what is already known about your personal and family history.
Positive Result
A positive result means that a harmful or likely harmful inherited genetic variant was identified. Depending on the gene involved, this information may help your care team estimate certain cancer risks and discuss whether changes in screening, risk-reduction strategies or other aspects of care may be appropriate.
Negative Result
A negative result means that testing did not identify a harmful inherited variant in the genes that were examined. It does not always mean that your cancer risk is average. Family history and other clinical factors can still indicate increased risk, particularly when there is a strong pattern of cancer in the family that current genetic testing does not explain.
Variant of Uncertain Significance
Sometimes testing identifies a genetic difference, called a variant of uncertain significance, for which there is not enough evidence to know whether it affects cancer risk. A variant of uncertain significance is not the same as a positive result and generally should not be treated as evidence that you have an inherited cancer syndrome. Your genetics team can explain what the finding means and whether its classification changes as more information becomes available.
What Can Genetic Information Mean for Your Family?
Because inherited genetic changes can be passed through families, a result may provide useful information not only for you but also for certain relatives. When a harmful inherited variant is identified, relatives may have the option of genetic counseling and testing to determine whether they inherited the same change.
Genetic information can also help families understand patterns of cancer that may previously have seemed unrelated. At the same time, a negative genetic test does not erase a significant family history. Genetic counselors can help put test results into context and explain what the information may mean for you and your relatives without assuming that everyone in a family has the same level of risk.
High-Risk Breast Cancer Program
Some people have an increased risk of developing breast cancer because of an inherited genetic variant, while others may have elevated risk based on family history, previous breast findings or a combination of factors. A negative genetic test does not necessarily mean that additional screening or risk management is unnecessary.
At the Margie Petersen Breast Center, our High-Risk Program brings this information together to help determine an appropriate plan for ongoing care. Breast specialists and genetics professionals can consider your personal history, family history, genetic test results and other risk factors when discussing screening and risk-reduction options.
Managing Increased Breast Cancer Risk
Learning that you have an increased risk of breast cancer does not mean that you will develop cancer. It can, however, provide an opportunity to develop a more individualized approach to screening and risk reduction. The appropriate strategy depends on the level and source of your risk, your age, health history and personal priorities.
Enhanced Breast Cancer Screening
Some people at increased risk may benefit from earlier, more frequent or additional breast imaging. Depending on your individual risk, this may include mammography and supplemental breast imaging such as MRI. Your care team can recommend a screening plan based on your overall risk rather than a genetic test result alone.
Medications to Reduce Risk
For some people at increased risk, medications that affect hormone activity may reduce the likelihood of developing certain types of breast cancer. Whether medication is appropriate depends on your individual risk factors, health history and the potential benefits and side effects of treatment.
Risk-Reducing Surgery
For selected people with substantially increased inherited breast cancer risk, risk-reducing surgery may be considered. This is a highly individualized decision based on the gene involved, estimated cancer risk, family and personal history, age and personal priorities, and should be discussed carefully with your care team.
Frequently Asked Questions About Genetics and Breast Cancer Risk
Do I need a family history of breast cancer to consider genetic testing?
No. Family history is an important part of assessing inherited cancer risk, but genetic testing may be appropriate even when there is no strong history of breast cancer in the family. Your own cancer diagnosis, other cancers in the family, ancestry and additional clinical factors can also help determine whether testing may be useful.
Can I still be at increased risk if my genetic test is negative?
Yes. A negative genetic test does not necessarily mean that your breast cancer risk is the same as someone without a significant personal or family history. Your care team can consider your genetic test results together with family history, previous breast findings and other factors when estimating risk and recommending screening.
Does a positive genetic test mean I will develop cancer?
No. A positive result identifies an inherited genetic variant associated with increased cancer risk, but it does not predict with certainty whether or when cancer will develop. The result can help your care team better understand that risk and discuss appropriate screening and risk-reduction strategies.
Can my genetic test results affect my relatives?
Yes. Because inherited genetic variants can be passed through families, identifying a harmful variant may provide useful information for certain relatives. Genetic counseling can help determine which family members may benefit from learning about the result and considering testing of their own.
Can genetic testing affect breast cancer treatment?
For some people who have already been diagnosed with breast cancer, inherited genetic information can contribute to treatment planning as well as future cancer-risk management. How a result affects care depends on the gene involved, characteristics of the cancer and other clinical factors, so your oncology team can explain whether the information is relevant to your treatment.
You do not need to understand your genetic risk or know whether testing is appropriate before reaching out. The Breast Center team can help review your personal and family history, answer your questions and determine what next step may be appropriate for you.
Talk With Our Breast Clinic Team
The Breast Health Clinic can be reached at (310) 582-7209. If you have questions about a new breast symptom, need an evaluation or would like help determining your next step, call and a member of our team can assist you.
