Assessing Breast Cancer Risk Through Genetic Counseling and Testing

Acknowledging that breast cancer can be triggered by genetic mutations inherited from one or both parents is crucial. While some mutations may not be harmful, certain genetic variations can heighten an individual's vulnerability to certain diseases. Thus, it is imperative to thoroughly understand the potential genetic factors that may play a role in the onset and progression of breast cancer. Genetic mutations and their possible link to breast cancer can be concerning. Seeking genetic counseling and testing can provide valuable insight and help individuals make informed decisions about their medical care. A healthcare provider will work with them to create a plan tailored to their needs. By taking proactive steps toward understanding breast cancer risks and testing, individuals can feel reassured and confident in making the best choices for themselves.

Genetic testing looks for gene, chromosome, and protein mutations through blood, saliva, and cheek swab samples. The results of a genetic test can confirm or rule out the presence of a suspected genetic condition or determine the likelihood of a person developing or passing on a genetic disorder.

There are a few gene mutations that are currently known to increase breast cancer risk:

• BRCA1
• BRCA2
• PALB2
• CHEK2
• ATM
• CDH1
• PTEN
• TP53

However, the most significant genes that affect breast cancer risk are the BRCA1 and BRCA2 genes. Women and men who have BRCA gene mutations have a significantly increased risk and increased risk, respectively, of getting breast cancer, ovarian cancer (or prostate cancer for men), pancreatic cancer, and possibly some other cancers.

Several types of genetic testing are available; the type recommended to you will depend on your medical and family history and what condition you’re being tested for. There is currently no genetic test that can detect all genetic conditions.

Single gene testing

Single-gene tests look for mutations in only one gene. This test is usually done when the doctor suspects you have symptoms of a specific condition. The test will look for mutations in that gene. Depending on the situation, the test may look for a specific mutation (for those with family members with a known mutation) or many different mutations within a particular gene.

Panel gene testing

Panel gene testing tests for changes in multiple genes in one test. They are typically used for conditions caused by mutations in multiple genes or if a person’s symptoms may fit a wide variety of conditions. For example, several different types of gene mutations can lead to an increased risk of getting breast cancer.

Large-scale testing or genomic testing

Large-scale testing looks at more than just a few genes. These are generally recommended for people with complex medical histories. Besides knowing about the condition the person was being tested for, the results of such tests can also show unrelated findings that may reveal gene mutations related to other conditions. Large-scale testing includes:

• Exome sequencing

Whole exome tests look at all the genes, and medical exome tests look only at the genes related to medical conditions.

• Genome sequencing

The genome sequencing test is the largest genetic test and looks at all of a person’s DNA, not just the genes.

Before you choose to get a genetic test, it is important to understand its benefits and limitations. Typically, your healthcare provider will inform you of all the benefits and limitations of genetic testing for you to make an informed decision. Here are a few benefits and limitations that come with genetic testing:

Benefits

• It clears uncertainties about having certain mutations and the risks of diseases that come along with it.
• Directs people with confirmed disease-causing genetic mutations toward prevention and management strategies.
• It helps some people to make decisions about having children as their mutations may be passed on to them.

Limitations

• While genetic tests for breast cancer do not involve physical risks, people who take them are still at risk of emotional, social, and financial consequences.
• Some people may feel anger, anxiety, depression, and guilt about the obtained results.
• Results may cause tension within the family.
• Testing may be expensive depending on the complexity and extensiveness of the test and may cause financial strain on some.

For genetic testing for breast cancer, genetic testing can be done on samples of blood, saliva, or from a swab on the inside of your cheek. The samples will be sent to a lab for testing. Getting the results may take a few days to a few weeks.

It is important to know the different kinds of results that you may receive from the genetic test. You may get one of the following results:

• Positive for a mutation that was tested for

If you receive a positive result for a mutation, it is natural to feel anxious and uncertain about what it means for your health. While it may increase your risk of developing breast cancer, it is important to remember that a positive result doesn't necessarily mean you will get the disease. Management strategies are available to help reduce your risk, and your healthcare team is there to support you at every step.

• Negative for the mutation(s) tested for

It is understandable to feel relieved when a test shows a negative result for a certain mutation. However, it is essential to remember that there could still be other mutations that were not tested for. These mutations might also increase the risk of developing breast cancer. It is important to remember that if none of your gene mutations are associated with breast cancer, then your risk of getting it is average, similar to that of most people.

• Inconclusive

Some test results may come back inconclusive. This happens when the test finds mutations, but it is unknown if these mutations are naturally occurring or disease-causing, as everyone has common, natural variations in their genes that do not affect health. Results like this are inconclusive and do not give a definite answer regarding a diagnosis or the likelihood of developing breast cancer.

It is normal to feel confused or overwhelmed when receiving the results of genetic testing. Rest assured that your genetic counselor is trained to help you understand the meaning of the results. They are equipped to answer any questions you may have and provide you with valuable advice on the appropriate steps to take next. Remember that you do not have to navigate this journey alone; resources are available to help you along the way.

In recent years, direct-to-consumer genetic tests have gained popularity. These tests typically require a simple cheek swab, and the results are delivered via an app or website a few weeks later. While they can provide some information about a person's health conditions, they only test for a limited number of mutations. They cannot replace more comprehensive lab-based genetic testing, counseling, or screening for a proper diagnosis. It is always best to consult a medical professional before making significant decisions.