Genetic testing examines certain genes with known links to breast cancer. The presence of these mutations increases a person’s likelihood of developing breast cancer. Genetic testing may not be suitable for everyone.

The following article describes genetic testing for breast cancer, the results, next steps, and more.

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Genetic testing can help to identify whether a person has any genetic mutations that can increase their chance of developing breast cancer in the future. According to the American Cancer Society (ACS), approximately 5–10% of breast cancer cases occur as a result of hereditary genetic mutations.

Several genes can increase a person’s risk, but the most common are BRCA1 or BRCA2 gene mutations.

Genetic testing typically looks at BRCA1 and BRCA2 genes.

Less often, a healthcare professional may suggest genetic testing for the following genes:

  • PALB2
  • CHEK2
  • ATM
  • PTEN
  • TP53

If test results indicate that a person has a gene that can increase their breast cancer risk, a doctor can work with them to determine an appropriate screening plan to help detect cancer sooner if it develops.

Learn more about the genes that can cause breast cancer here.

A genetic counselor may recommend a multigene panel, which can check for a variety of different types of gene mutations or variants in one test, including the BRCA genes.

How accurate are they?

According to the National Cancer Institute (NCI), genetic testing is quite accurate. But there are no tests that are 100% error-free.

Not all people need genetic testing for breast cancer. But there are several groups of people who are at higher risk, so may benefit from genetic testing.

The ACS suggests that the following people may benefit from genetic testing:

  • those with a family history of a BRCA mutation
  • females with a past diagnosis of ovarian cancer, pancreatic cancer, or breast cancer
  • males with breast cancer, pancreatic cancer, or metastatic prostate cancer
  • those with a family history of early onset breast cancer
  • those with a close family member with a history of metastatic prostate cancer, ovarian cancer, or pancreatic cancer

Additionally, those who already have a breast cancer diagnosis may undergo genetic testing if:

  • they received a diagnosis between ages 45–50 years or younger
  • they have a diagnosis of triple-negative breast cancer at age 60 years or younger
  • they are of Ashkenazi Jewish descent
  • they have a family history of ovarian cancer, breast cancer, pancreatic cancer, or prostate cancer
  • they have received a diagnosis of breast cancer for a second time

Before going for testing, a person should consider speaking with a doctor about their potential risk.

The Centers for Disease Control and Prevention (CDC) note that a doctor may refer a person for genetic counseling if they meet any of the criteria based on the guidelines above. They will take a detailed medical and family history, discuss testing options, and review results. They will also discuss the cost and potential risks of the test.

If a doctor or genetic counselor decides that genetic testing may be useful, they can help people set up the test.

Once a person decides to get tested, the procedure is simple. Testing typically requires one of the following:

  • blood sample
  • saliva sample
  • cheek swab

Following the test, the genetic counselor will go over the results and help determine what, if any, additional steps to take.

A doctor sends test samples to a commercial lab for analysis.

Results can take between 2–4 weeks to come back. But this may take longer depending on the laboratory, a person’s insurance, and other factors.

When the lab sends the results, a person should make an appointment with the genetic counselor or doctor to review the results.

There are four possible results that a lab may send back. They are:

  • Positive result: This means that the laboratory found a genetic variant that has connections to breast cancer. A positive result can:
    • help to guide management techniques to help reduce a person’s chance of developing breast cancer
    • provide information to other family members to help them make decisions about their own health
    • confirm that breast cancer likely occurred as a result of the gene, and help to guide treatment options for those who have breast cancer
  • Negative result: This means that the laboratory did not find a gene that can increase the chance of breast cancer. If a family member has a gene related to breast cancer, a negative result can confirm that a person has not inherited the gene.
  • Variant of uncertain significance: This means that the results are uncertain. Variants that were uncertain in the past are typically reclassified as benign. But in some cases, the variant may have a connection to an increased chance of breast cancer. A doctor may advise that a person returns for genetic testing a few years later.
  • Benign variant: This means that there is a genetic change that is common among those without cancer.

The next steps to take can depend on the result.

Negative result

According to Breastcancer.org, if a person’s test result was negative but they have a family member with a breast cancer gene, their risk of breast cancer is the same as those of the general population, which is 12–13% over the course of their lifetime.

Males who receive a negative result have the same risk of developing breast cancer as other males.

Females with an average breast cancer risk should:

  • practice regular self-examinations and get regular breast exams
  • get regular mammograms
  • eat a well-balanced diet
  • exercise regularly
  • minimize their alcohol intake

Positive result

If a person has breast cancer and receives a positive result, a healthcare professional will discuss the potential treatment options. For example, testing positive for a BRCA1 or BRCA2 gene means that a person may be a good candidate for hormonal therapy.

People may also wish to discuss their chance of developing secondary breast cancer or ovarian cancer with a healthcare professional.

For those who do not have breast cancer, they may wish to:

  • speak with a doctor to discuss the steps they will need to take to help reduce their chance of developing breast cancer
  • consider making a plan for regular screenings
  • discuss preventive surgery with a doctor

Getting positive test results does not mean a person will definitely develop breast cancer. It just means they have a higher risk of developing breast cancer in the future.

Uncertain result

A person with an uncertain result may still have a higher chance of developing breast cancer. As a result, people should discuss their options with a doctor.

People may wish to consider the following options:

  • talking to a healthcare professional about beginning annual mammograms
  • talking to a healthcare professional about undergoing ovarian cancer screening
  • having a breast exam every 6 months
  • maintaining a balanced, moderate lifestyle
  • discussing preventive surgery with a healthcare professional

Genetic testing can provide a person with a few potential benefits.

They include:

  • peace of mind if the test is negative
  • being able to take steps to help reduce their chance of developing cancer if the result is positive
  • being able to make decisions about potential treatment options
  • providing an opportunity for family members to learn about their cancer risk

Genetic testing for breast cancer may not be appropriate for everyone. A person should speak with a doctor before agreeing to testing.

Some potential cons include:

  • anxiety, depression, or other mental health concerns due to a positive result
  • cost of testing and follow-up appointments, if a person does not have insurance
  • uncertainty and stress due to abnormal or uncertain results
  • feelings of guilt if a person has passed on the genes

The NCI warns that people may experience privacy and discrimination concerns. The test results may be visible to people or organizations that have legal access to their medical records. This can include insurance companies and potential employers.

The Genetic Information Nondiscrimination Act (GINA) of 2008 prohibits discrimination based on a person’s genetic information. GINA can protect people regarding a person’s employment or eligibility for health insurance. But it does not cover:

  • life insurance
  • disability insurance
  • long-term care insurance
  • those in the military

The ACS notes that genetic testing can be expensive, and insurance companies may only partially cover the test.

According to BreastCancer.org, costs can range from $300–$5,000 for testing without insurance coverage. Costs vary based on the facility, as well as how many different genes the tests examine.

People without insurance may be able to get a reduced rate. Doctor’s offices may also be able to provide information on potential assistance programs.

Some companies now offer genetic breast cancer screening kits that a person can use at home. A person submits a saliva sample or mouth swab through the post and gets their results over the phone, by mail, or on a secure website.

But the NCI notes that these kits typically test for common inherited genetic variants that only slightly increase a person’s chance of developing breast cancer. The genetic tests that a healthcare professional orders look for genetic variants that lead to a moderate to high increase in risk.

Additionally, BreastCancer.org notes that while the tests may be helpful for some people, many insurance companies will only pay for one genetic test during a person’s lifetime. This means that using it on a home test may prevent a person from getting coverage for a more comprehensive test.

Genetic testing can help to identify if a person has inherited a gene that increases their chance of developing breast cancer. But it is not suitable for everyone.

Doctors typically recommend it for people at a higher risk of having a mutation on a gene that can increase a person’s risk of developing breast cancer. Results can show that a person has an elevated risk factor, but this can lead to emotional distress, and may also make it more difficult for a person to get life insurance.

If a person decides to undergo genetic testing, they should speak with their doctor first. They should also talk with a genetic counselor before and after genetic testing. They can help to explain the results and develop a plan moving forward.