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How Do They Do Genetic Testing For Breast Cancer

Does Someone Who Inherits A Cancer Susceptibility Variant Always Get Cancer

How does genetic testing work for breast cancer patients?

No. Even if a cancer susceptibility variant is present in a family, it does not necessarily mean that everyone who inherits the variant will develop cancer. Several factors influence whether a given person with the variant will actually develop cancer. One is the penetrance of the variant. When not all people who carry a variant go on to develop the disease associated with that variant, it is said to have incomplete or reduced penetrance. Hereditary cancer syndromes can also vary in their expressivitythat is, people who inherit the variant may vary in the extent to which they show signs and symptoms of the syndrome, including the development of associated cancers. Lifestyle factors and environmental risks can also influence disease expression.

What Is Genetic Testing For Breast Cancer

Genetic testing uses healthy cells obtained from a blood or saliva test. We study the DNA of the cells to look for inherited changes or differences, also called mutations, that we know prevent the gene from doing the job its supposed to do, which is to repair damage to DNA.

As we go through life, were exposed to harmful elements in the environment, like chemicals, pesticides and radiation. These exposures can damage our cellular DNA.

When cells divide in our bodies, the DNA is copied. When its copied correctly, the copy is identical to the original. But sometimes, errors happen during this process. The job of some genes is to repair those errors when they occur.

We’ve learned that in some people, and in some families, one of these genes isnt able to repair DNA damage the way its supposed to, and this malfunctioning gene is passed down from generation to generation. Anyone who has this type of genetic mutation has a higher-than-average risk for certain types of cancer associated with that mutation.

Affordable Care Act Coverage

The Affordable Care Act requires insurance plans that began on or after August 1, 2012 to cover genetic testing costs .

If you have a BRCA1/2 inherited gene mutation, the Affordable Care Act also requires coverage of counseling to help you decide if taking a medication to lower the risk of breast cancer is right for you.

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How Are These Tests Done

For the BRCA gene tests, your doctor or nurse will take a sample of your blood or a swab of saliva from the inside of your cheek. The blood or saliva sample then goes to a lab, where technicians test it for the BRCA gene mutations.

Your doctor performs HER2 gene tests on breast cells removed during a biopsy. There are three ways to do a biopsy:

  • Fine needle aspiration biopsy removes cells and fluid with a very thin needle.
  • Core needle biopsy removes a small sample of breast tissue with a larger, hollow needle.
  • Surgical biopsy makes a small cut in the breast during a surgical procedure and removes a piece of tissue.

You and your doctor will get a copy of the results, which come in the form of a pathology report. This report includes information on the type, size, shape, and appearance of your cancer cells, and how quickly theyre likely to grow. The results can help guide your treatment.

What A Positive Result Means

Chromosomal Differences

If your predictive genetic test result is positive, it means you have a faulty gene that raises your risk of developing cancer.

It does not mean you are guaranteed to get cancer your genes only partly influence your future health risks. Other factors, such as your medical history, lifestyle and your environment, also play a role.

If you have one of the faulty BRCA genes, there is a 50% chance you will pass this on to any children you have and a 50% chance that each of your siblings also has it.

You may want to discuss your results with other members of your family, who may also be affected. Staff at the genetics clinic will discuss with you how a positive or negative result will affect your life and your relationships with your family.

You can read more about BRCA1 and BRCA2 in the beginner’s guide to BRCA1 and BRCA2 produced by The Royal Marsden NHS Foundation Trust.

Insurance companies cannot ask you to disclose the results of predictive genetic tests for the majority of policies, but this may change in the future.

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What Are Some Of The Possible Harms Of Genetic Testing For Inherited Cancer Susceptibility Syndromes

Genetic testing can have potential emotional, social, and financial harms, including:

  • Psychological stress of learning that one has a genetic variant that increases cancer risk and having to decide whether to share those findings with blood relatives
  • An uninformative test results, such as a report of a variant of uncertain significance , increases uncertainty and may increase stress until results are clarified
  • Survivor guilt upon learning that one doesnt have a harmful variant that is present on other members of the family
  • Cost of testing itself and additional follow-up testing, if not covered by insurance
  • Privacy and discrimination issues

How Do I Decide Whether To Have A Genetic Test

Before you have a test, the genetic counsellor will talk to you about what your options are if you do have a faulty gene. This is usually part of the process of deciding whether to have the test or not. The options will depend on:

  • the particular gene fault that you may have
  • which cancers you are at increased risk of developing
  • your age and plans for the future

If a faulty gene is found, you may have:

  • regular screening to pick up cancers early
  • treatment to reduce the risk of cancer, such as medicines or surgery

Read about possible screening and treatment options on the page about getting your genetic test results.

Making a decision about whether to have genetic testing can be difficult. It is normal to feel anxious. Thinking about the possibility of getting cancer is difficult. It may also bring back emotions you felt when other family members were diagnosed with cancer and what they went through.

It is important to take time to think it through. Before you decide, it can help to think about these questions:

  • how do you feel about having a test?
  • what will the result really mean for you and your family?
  • what will you do if the result is positive?
  • how will you feel if the result is positive?
  • will you feel reassured by a negative test?
  • would you rather not know if you have an increased risk of cancer?
  • is there treatment to reduce your risk?
  • if there is treatment, would you consider having it?
  • what will happen if you decide not to have the test could you have regular screening?

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Why Do Genetic Testing For Cancer

The biggest reason for me to do genetic testing is that some of the genetic mutations increase your risk for other types of cancer. If I test positive, I may need to take steps to reduce my risk of getting these other cancers. One of these is ovarian cancer. Unlike breast cancer, we dont have good screening tests to find ovarian cancer early. If I’m at higher risk, doctors might recommend I get my ovaries and fallopian tubes removed around age 40.

At the time of this appointment, Im 37. I think about the two major surgeries Ive already had and how much I dont want to go through another one.

This is a lot of information to take in, Thomas says. How are you feeling?

I pause for a deep breath and admit I feel overwhelmed. But Im really grateful for the information. Id rather know, so I can do everything I need to do to prevent cancer.

Thomas reminds me this isnt an emergency. I dont have cancer yet. The profiler says I only have a 3% chance of getting it in the next decade. So we have time to get the information, think about it, and make a plan.

Thomas doesnt push me either way on testing. I decide I want to do it, but its totally up to me.

Having an appointment with me does not mean you have to go forward with testing, she says. Some people want to just come and hear the information. People sometimes feel like they need to be prepared for testing when all they actually need to be prepared for is to have a conversation.

Should I Be Tested For Genetic Mutations

Genetic testing for cancer

At-risk families can take blood tests to look for mutations in these genes.

You may want to discuss genetic testing with your doctor if:

  • You have two or more blood relatives — mother, sister, aunt, cousin, or daughter — with premenopausal breast cancer or ovarian cancer diagnosed at any age.
  • You were diagnosed with breast cancer, especially before menopause, and have a blood relative with breast or ovarian cancer.
  • You were diagnosed with ovarian cancer and you have blood relatives who have had ovarian or breast cancer.
  • A male in your family has or had breast cancer.
  • You or a family member has been diagnosed with bilateral breast cancer .
  • You were diagnosed with triple-negative breast cancer before the age of 60.
  • You are related to someone who has a BRCA1 or BRCA2 mutation.
  • You are of Ashkenazi Jewish descent and have had breast or ovarian cancer or have blood relatives who have had breast or ovarian cancer.

Continued

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Online Tools To Help You Talk With Your Health Care Provider

There are a few online tools to help you talk with your health care provider about your risk of having a BRCA1/2 inherited gene mutation and your risk of breast cancer.

Keep in mind online tools cant tell you whether or not you have a BRCA1/2 gene mutation or if you will get breast cancer. However, they may help you talk with your health care provider or a genetic counselor about these risks.

What Are The Possible Results Of A Genetic Test

Patients are sometimes disappointed to find that the results of genetic testing may not be clear and may not provide the answers theyre looking for. Possible test results and what they mean include:

  • Positive: A positive test result means we found an inherited risk for cancer.
  • Negative: A negative test result means we found no differences in any of the genes that we looked at.
  • Inconclusive: An inconclusive test result means we found a genetic difference thats unclear. This result may also be called a variant of uncertain significance. This means we’re not sure whether the difference we found could contribute to the development of cancer.

When someone tests negative for a known mutation in their family, this is called a true negative test result. The vast majority of people with true negative test results are at average risk for cancer.

Sometimes negative and inconclusive results are referred to as uninformative results, meaning the genetic testing did not provide an explanation for the personal or family history of cancer. This means we found a difference in a gene, but its impact on that gene’s function, and therefore the risk for cancer, is unknown.

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Genetic Testing For Women Diagnosed With Breast Cancer

All women diagnosed with breast cancer at age 45 or younger would benefit from genetic counseling and testing.

Women diagnosed with breast cancer between ages 46-50 would benefit from genetic counseling and testing if they have any of the following:

  • a small family.
  • pancreatic cancer.
  • metastatic prostate cancer.
  • 2 or more first-, second- or third-degree relatives with breast cancer or prostate cancer at any age
  • 3 or more separate diagnoses of breast cancer in patient and/or close relatives combined.
  • lobular breast cancer with a personal or family history of diffuse gastric cancer.
  • metastatic breast cancer to determine eligibility for treatment with the targeted therapies Lynparza or Talzenna.
  • early stage breast cancer at high risk for recurrence to determine eligibility for maintenance therapy with the targeted therapy Lynparza.
  • Women with the following are unlikely to have an inherited gene mutation:

    • Diagnosed with breast cancer after 65 who have:
    • no prior history of breast, ovarian or pancreatic cancer.
    • no first-,second-, or third-degree relative who was diagnosed with breast, ovarian, pancreatic or prostate cancer.
    • no Eastern European Jewish ancestry.

    Variant Of Uncertain Significance Result

    Genetic Testing for Breast Cancer: What Does The BRCA1 ...

    Getting a result of a variant of uncertain significance can be confusing and frustrating.

    With BRCA1/2 testing, most VUS results are later found to be benign variants . However, theres a small chance the VUS will turn out to be a gene mutation that increases breast cancer risk.

    With expanded panel testing, youre more likely to get a VUS result because more genes are being tested.

    Not knowing whether the VUS helps explain your personal or family history of cancer may add to the stress of an already trying process.

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    How Does Genetic Testing Work

    Testing for BRCA1, BRCA2 and other inherited gene mutations requires a blood or saliva sample.

    Its best to have genetic testing done in a clinically-approved lab certified by the Clinical Laboratory Improvement Amendments . You can get this testing through your health care provider or a genetic counselor.

    Your health care provider or a genetic counselor can help you understand the test results and give you the most up-to-date medical recommendations.

    If you use a direct-to-consumer genetic test, have the findings confirmed by genetic testing done in a clinically-approved lab certified by the CLIA . This ensures the results are complete and correct. Your health care provider or a genetic counselor can arrange this testing for you.

    Who Will Be Offered Genetic Testing

    If you have been assessed as being at high risk of breast cancer, you may be offered genetic testing to find out if you have inherited an altered gene. This is usually known as being a gene carrier. The most common inherited altered genes are called BRCA1, BRCA2 and TP53.

    Your genetics team will tell you if genetic testing is an option for you. Genetic testing will try to find out if there is a known altered gene that runs in your family. If genetic testing is an option for you, it is your decision whether or not to have the test.

    In the NHS, genetic testing is usually only available through a genetics centre and after youve had genetic counselling. However, at some hospitals pre-test counselling and genetic testing may be provided by the breast and gynaecology specialist teams , and if post-test counselling is needed this would be done by the genetics team.

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    Genetic Testing To Learn About Your Risk Of Breast And Ovarian Cancer: Questions For The Doctor

  • Genetic Testing to Learn About Your Risk of Breast and Ovarian Cancer: Questions for the doctor
  • Genetic counseling and testing can help you understand your risk of some kinds of cancer. Genetic tests can show whether you were born with mutations in certain genes that increase your risk of cancer.

    If you were born with certain mutations in the BRCA1 gene or the BRCA2 gene, you are at higher risk of developing breast and ovarian cancer. You may also be at higher risk of developing other types of cancers.

    Talk with your doctor about genetic testing to learn about your risk of breast and ovarian cancers if you have:

    • A family member who had breast cancer before age 50
    • A family member who had cancer in both breasts
    • A family member who had both breast and ovarian cancer
    • A male family member who had breast cancer
    • Two or more family members who had breast cancer
    • Eastern European Jewish heritage

    You may also want to ask about genetic testing if you’ve already had breast or ovarian cancer.

    If genetic tests show that you’re at higher risk of developing breast or ovarian cancer or of getting cancer a second time you and your doctor can discuss options for managing your risk.

    Why Do Some People Decide Not To Have The Test

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    After looking at the advantages and disadvantages of testing, some people choose not to have a genetic test. They may feel that they dont want to know if they have a higher than normal cancer risk.

    Some people decide they dont want any preventative treatment even if they have a faulty gene. So they may not feel they have anything to gain by having the test.

    Only you can decide what is best for you.

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    When Is Genetic Testing Not Recommended

    Theres only a very small chance your family carries a BRCA1/2 inherited gene mutation if you or a family member is the only person in your family with breast cancer .

    Although you always have the option of being tested, in most cases, genetic testing isnt recommended when theres a very low chance of finding a mutation. Its strongly recommended you speak with a genetic counselor before deciding whether to have genetic testing.

    Most breast cancers are not due to a BRCA1/2 or other inherited gene mutation linked to breast cancer .

    Predictive Genetic Tests For Cancer Risk Genes

    Cancer is not usually inherited, but some types mainly breast, ovarian, colorectal and prostate cancer can be strongly influenced by genes and can run in families.

    We all carry certain genes that are normally protective against cancer. These genes correct any DNA damage that naturally happens when cells divide.

    Inheriting faulty versions or “variants” of these genes significantly raises your risk of developing cancer, because the altered genes cannot repair the damaged cells, which can build up and form a tumour.

    BRCA1 and BRCA2 are examples of genes that raise your cancer risk if they become altered. Having a variant BRCA gene greatly increases a woman’s chance of developing breast cancer and ovarian cancer. They also increase a man’s chance of developing male breast cancer and prostate cancer.

    BRCA genes are not the only cancer risk genes. Researchers recently identified more than 100 new gene variants associated with an increased risk of breast, prostate and ovarian cancer. Individually, these new gene variants only slightly increase the risk of cancer, but a combination could mean a high risk overall.

    If you or your partner have a high-risk cancer gene, such as an altered version of BRCA1, it can be passed on to any children you have.

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