Getting Genetic Test Results
Commercial laboratories often report results in two to four weeks, and research centers tend to report results after a minimum of 4 weeks.
A critical part of genetic risk assessment is the responsible and sensitive disclosure of test results. Typically, laboratories send your test results to your doctor or genetic counselor. So, it’s a good idea to ask your doctor or genetic counselor when, how, and where you can expect to get your test results.
Myriad Genetic Laboratories include a riskScore with your genetic test results. The riskScore combines genetic markers with a person’s family and personal history to offer an estimate of breast cancer risk, especially for people who test negative for a gene mutation linked to breast cancer. Still, it’s important to know the following:
The riskScore is only validated for people with European and Ashkenazi Jewish ancestry. The results may be inaccurate for people with different ancestry.
The riskScore very much depends on the accuracy of the personal and family history information you provide with the sample. The riskScore may be inaccurate if your personal and family history — such as how old you were when you got your first period, whether you’ve had a breast biopsy, how old you were when you gave birth to your first child, or how old you were when you started menopause — is incomplete.
The National Comprehensive Cancer Network, an alliance of the world’s leading cancer centers, does not list the riskScore as a validated method for assessing breast cancer risk in its current guidelines.
If you get your results in person, you may wish to take someone with you. It can be very reassuring to have someone with you if you test positive for a genetic mutation. It also may be helpful to have another person with you to listen and help you remember everything the genetic counselor explains. You don’t have to go through this process alone and without support.
The recommendations that follow are based on currently available but limited information — and common sense.
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What to do if your genetic test results are negative
If your family has a defined breast cancer gene abnormality but you test negative for the abnormality, you have between a 12% and 13% risk of developing breast cancer in your lifetime, which is considered to be the same as the general population. Men who test negative for a known breast cancer gene abnormality have the same very low risk of developing breast cancer as men in the general population. Regardless of gender, testing negative for a cancer-related mutation means you cannot pass a genetic abnormality that runs in the family to any children you may have.
If you have an average risk of developing breast cancer, you can follow the screening and lifestyle guidelines recommended for most people:
Practice regular breast self-examinations and get annual or semiannual clinical breast exams, depending on your doctor’s recommendations
Have screening mammograms following the current guidelines for women of average risk: a baseline mammogram at age 40 and annual mammograms after age 40.
Maintain a healthy lifestyle by eating a low-fat, well-balanced diet; exercising regularly; maintaining a healthy weight; and minimizing your alcohol intake. These strategies can help improve your general health and sense of well-being and possibly lower your breast cancer risk.
What to do if your genetic test results are positive
People who test positive for an abnormal BRCA1, BRCA2, or PALB2 gene and have never been diagnosed with breast cancer have a much higher-than-average risk of developing the disease.
The average lifetime risk of breast cancer for women is about 12%. Women with a BRCA1 or BRCA2 mutation have up to a 72% risk of developing breast cancer in their lifetime — about 6 times higher than women who do not have the mutation. Lifetime risk of ovarian cancer is significantly elevated as well: 17% to 44%, versus just under 2% for the general population.
Men with BRCA abnormalities have a higher lifetime risk of male breast cancer, especially if the BRCA2 gene is affected. One study found that men with a BRCA2 mutation have a 7% lifetime risk of developing breast cancer. They also are at increased risk of developing prostate cancer.
Women with an abnormal PALB2 gene have a 33% to 58% lifetime risk of developing breast cancer. Researchers believe that people with an abnormal PALB2 gene may have an increased risk of developing male breast cancer, pancreatic cancer, and ovarian cancer, but are still investigating the exact degree of increase. Research on the PALB2 gene continues.
Regardless of gender, testing positive for a BRCA1, BRCA2, or PALB2 abnormality means there is a 50% chance you could pass the cancer-related mutation on to any children you may have.
While rare, it’s possible for a person to have one BRCA1 and one BRCA2 mutation. Usually, this occurs in people with Ashkenazi Jewish ancestry because of the higher carrier frequency. Screening and risk-reduction recommendations are the same for people who have both mutations as they are for a person who has just one mutation. People who have both mutations have a 50% chance of passing each mutation to any children they may have.
Researchers are working to deepen their understanding of how breast cancers in women with BRCA mutations may differ from other breast cancers. Some of their findings include the following:
Breast cancers in women with BRCA1 abnormalities are more likely to have high-grade cell growth and be estrogen receptor–negative — meaning that the cancer’s growth is not fueled by the hormone estrogen. Breast cancer with these two characteristics responds better to chemotherapy than to hormonal (anti-estrogen) therapy.
BRCA1- and BRCA2-related cancers often test negative for overexpression of the gene known as HER2/neu. This genetic abnormality is not inherited but can develop in women over time. When the HER2 gene is overexpressed, the cancer cells have too many human epidermal growth factor receptors (HER2). HER2 receptors receive signals that stimulate the growth of breast cancer cells. HER2-positive breast cancer is considered to be a more aggressive form of the disease, but it can be treated with Herceptin (chemical name: trastuzumab), and other medicines that target the HER2 receptors. Most BRCA1- and BRCA2-related cancers cannot be treated with anti-HER2 treatments because they are HER2-negative.
Women with BRCA1 or BRCA2 gene abnormalities don’t have greater risk than other women of having multiple cancers in the same breast when they are diagnosed with breast cancer.
A 2005 study suggests that women diagnosed with ductal carcinoma in situ (DCIS) are just as likely to have inherited gene abnormalities as those diagnosed with invasive breast cancer.
It makes sense to ask your doctor to explain how BRCA status may affect your treatment decisions if you have a breast cancer gene abnormality and are then diagnosed with breast cancer. For example, if you have a BRCA1 mutation, the breast cancer is less likely to be estrogen receptor–positive, which means you may not be a candidate for treatment with hormonal therapy. If you have a BRCA2 mutation, however, you are more likely to be a candidate for hormonal therapy. Because research on the PALB2 gene is ongoing, it’s not clear yet if cancers caused by a PALB2 mutation are likely to have specific characteristics.
It’s also a good idea to talk with your doctor about reducing the risk of a new, second breast cancer or ovarian cancer. Women with breast cancer and a BRCA1 or BRCA2 abnormality have a significantly greater risk of developing a new, second breast cancer, as well as ovarian cancer.
Regardless of whether you’ve ever been diagnosed with breast cancer, a BRCA mutation means you are at much greater risk of developing breast and possibly ovarian cancer in the future. Research offers the following insights on strategies that can help lower those risks:
Preventive or prophylactic mastectomy — or removal of both breasts — can reduce breast cancer risk by about 90%. After someone with a genetic abnormality is diagnosed with breast cancer for the first time, the risk of developing a new breast cancer is approximately 3% every year, or approximately 15% throughout a 5-year period. After someone without a BRCA1 or BRCA2 mutation is diagnosed with breast cancer for the first time, the risk of developing a new breast cancer is only 1% every year.
Learn more about Prophylactic Mastectomy.
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Preventive or prophylactic salpingo-oophorectomy — or removal of both ovaries and fallopian tubes — can reduce breast cancer risk by as much as 50% when it is done before menopause, because it takes away the body’s main source of the hormone estrogen. It also can greatly reduce ovarian cancer risk. The timing of removing the ovaries differs depending on whether a person has a BRCA1 or BRCA2 abnormality. For those with a BRCA1 abnormality, the recommended timing of removing both ovaries and fallopian tubes is between the ages of 35 and 40. For those with a BRCA2 abnormality, removing ovaries and fallopian tubes can be considered between the ages of 40 and 45.
Learn more about Prophylactic Ovary Removal.
Hormonal therapy medicines include two selective estrogen receptor modulators (SERMs) and two aromatase inhibitors, which can reduce the risk of developing hormone receptor–positive breast cancer.
Tamoxifen can reduce the risk of first-time hormone receptor–positive breast cancer in postmenopausal and premenopausal people. (Certain medicines may interfere with tamoxifen’s protective effects.)
Evista (chemical name: raloxifene) can reduce the risk of first-time hormone receptor–positive breast cancer in postmenopausal people.
Aromasin (chemical name: exemestane), an aromatase inhibitor, can reduce the risk of first-time hormone receptor–positive breast cancer in postmenopausal people. The U.S. Food and Drug Administration (FDA) has not approved Aromasin for this specific type of cancer, but doctors may consider it a good alternative to tamoxifen or Evista.
Arimidex (chemical name: anastrozole), also an aromatase inhibitor, can reduce the risk of first-time hormone receptor–positive breast cancer in postmenopausal people. Like Aromasin, Arimidex isn’t approved by the FDA for this specific type of cancer, but doctors may consider it a good alternative to tamoxifen, Evista, or Aromasin.
Hormonal therapy medicines do not reduce the risk of hormone receptor–negative breast cancer.
Researchers believe that hormonal therapy medicines can likely lower breast cancer risk in people with an abnormal PALB2 gene, but specific studies are still needed.
People who want to reduce their breast cancer risk also can have more frequent cancer screenings. Although more frequent screenings do not guarantee early detection of cancer, doctors recommend this option for people who don’t want to have preventive (prophylactic) surgery.
You can work with your doctor to come up with a screening schedule that is right for you. The following is an example that you can amend, depending on your personal situation:
At age 25, begin annual breast MRIs or mammograms if breast MRIs are not available. You can begin to get screenings sooner if a family member has been diagnosed with breast cancer under the age of 30. Begin annual mammograms and breast MRIs between the ages of 30 and 75. Screenings should be considered on an individual basis for women over the age of 75. Doctors recommend that men receive yearly clinical breast exams and begin performing breast self-exams at age 35.
At age 25, begin annual pelvic exams with your gynecologist. Between ages 30 and 35, consider annual ovarian cancer screenings that include pelvic ultrasound with an intravaginal probe and blood tests for a special protein called CA-125.
Have a clinical breast exam every 6 months, and examine your breasts monthly.
Consider participating in a clinical trial testing new cancer prevention strategies and early detection methods.
Some people of childbearing age who test positive for a genetic mutation linked to cancer risk choose to use preimplantation genetic diagnosis (PGD) to prevent passing an abnormal gene mutation to their children. PGD can be done as part of the in-vitro fertilization (IVF) process. It can offer parents and their future children peace of mind, but it does involve a lot of time, effort, and expense. Learn more about Preimplantation Genetic Diagnosis.
What to do if you test positive for less common gene abnormalities
Inherited mutations in other genes besides BRCA1 or BRCA2 also have been linked with breast cancer risk. These gene abnormalities are much less common than mutations in BRCA1 or BRCA2, and don’t seem to increase risk as much. As a result, researchers haven’t studied these gene mutations as much as they’ve studied the BRCA genes.
Still, depending on your personal or family history of breast cancer and other cancers, your genetic counselor may order a genetic test that looks for mutations in the following genes:
mismatch repair genes (MLH1, MSH2, MSH6, PMS2, EPCAM)
These genes can be tested individually or as part of a larger gene panel that includes BRCA1 and BRCA2.
If you test positive for any of these abnormal genetic mutations, your genetic counselor can talk you through risk-reducing options, including increased screening, risk-reducing hormonal therapy, or risk-reducing surgery.
Learn more about the breast cancer risk factors linked to each of these inherited genetic mutations.
What to do if your genetic test results are uncertain
Sometimes, genetic testing results aren’t clear about whether you have an increased risk of developing breast cancer or other cancers. Your results may look as follows:
Uninformative or indeterminate: If you have a strong family history of breast or ovarian cancer, but all of you have tested negative for genetic abnormalities, there’s a chance that you have all inherited a genetic abnormality that researchers haven’t yet identified. If you tested negative for genetic abnormalities, but nobody in your family who has been diagnosed with breast cancer has gotten genetically tested, it’s also possible that you’ve inherited a still unidentified genetic abnormality.
Inconclusive or showing a variant of unknown significance: Sometimes a genetic test finds an unusual change, or variant, in genes that researchers have not clearly associated with increased breast cancer risk. It may become clearer whether the unknown variant is associated with cancer risk as more of your family members get tested. You also may need to keep in touch with your genetic counselor to find out whether more information becomes available about the unknown variant your genetic test found.
It’s normal for people who don’t get definite results from genetic testing to feel anxious. Speaking with your doctor and genetic counselor to figure out steps you can take next may help address any concerns you have.
Regardless of your genetic test results, you may still have a high breast cancer risk based on family history alone. Here are some strategies that people with high breast cancer risk follow:
Ask your doctor when you should begin annual mammograms and whether digital or 3D mammography may be beneficial. Discuss whether you should consider screening with breast MRIs.
Let your doctor know if ovarian cancer runs in your family, and ask whether you should have ovarian cancer screening with your gynecologist.
Have a clinical breast exam every 6 months, and examine your breasts monthly.
Consider participating in a clinical trial that is testing new methods of early detection and cancer prevention strategies.
Maintain a healthy lifestyle, and follow recommended nutrition and exercise guidelines.
Consider discussing risk-reducing surgery with your doctor.
Learn more about Breast Cancer Tests: Screening, Diagnosis, and Monitoring.
What to do if your genetic test finds variants of unknown significance
In a small number of cases, a genetic test can find a variant of unknown significance (VUS). This means there is a portion of a gene that looks different from the way it’s normally expected to look. More studies are needed before researchers can confirm whether the variant is a risk factor for breast cancer or whether it’s harmless. Research on unknown variants is ongoing.
“They actually do basic research as well as studies within families to determine whether the variant is damaging or not. Over time, variants get reclassified as to whether they’re mutations or just normal variations,” notes Cristina Nixon, MS, LCGC, a licensed certified genetic counselor with the Cancer Risk Assessment and Genetics Program at Main Line Health in Pennsylvania. She notes that the rates of VUS results vary depending on the gene. For example, the rate of a BRCA1 or BRCA2 VUS varies from 2% to 4% depending on the laboratory that performs the test. Sometimes a VUS is also referred to as an inconclusive finding.
Genetic counselors can help people understand a positive VUS result in relation to their family history and any of their relatives’ genetic test results. If many people in one family test positive for the same unknown variant, then the VUS may be responsible for that family’s increased cancer risk. But if many people in one family all share a known cancer-related mutation, a person’s VUS result may be less concerning.
“In either case, a VUS cannot be interpreted based on your family history alone. Some laboratories will study a VUS within a family to see if it is tracking with cancer. The more families with the VUS who are able to participate in a study, the more data the lab will have, which assists in determining whether the VUS is a mutation or normal gene variation,” says Cristina Nixon. If you don’t have many (or any) relatives who have gotten genetic testing, your genetic counselor can advise you on whether you should follow some of the same recommendations as people with a high breast cancer risk.
If you test positive for a VUS, it’s a good idea to keep in touch with your genetic counselor. Most testing laboratories send updates to your genetic counselor (who then updates you) if research finds a link between a variant and an increased breast cancer risk.
People react differently to the news that they have a VUS. “Some people are just so glad to hear that they don’t have a known harmful mutation and they stop listening after that point, and sometimes they just forget about it,” Cristina Nixon says. “I’ve called people to give them updated information, and they had forgotten they even had a variant! But I have others who get really concerned about it. It bothers them to know that something is there, but we don’t know if it means anything or not.”
Because the science is always changing, there can be rare instances in which two different testing laboratories classify the very same genetic alteration differently, according to Cristina Nixon. One laboratory can consider a genetic alteration a VUS because they need more evidence, while another laboratory might consider it to be harmful because they consider the evidence they found enough to link the mutation to higher cancer risk. Your genetic counselor can help you figure out how to interpret your results so you can determine what steps to take next.
— Last updated on June 29, 2022, 3:04 PM