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|Genetic Test Explained
This is a test which is sometimes offered to women with a history of either breast or ovary cancer in the family. The same test is used for both diseases.
The BRCA1 and BRCA2 are human genes which have been identified and classed as tumor suppressors. In normal healthy cells they help to prevent cells growing out of control. Mutations in these genes can be passed from generation to generation and have been linked to heredity ovarian and breast cancer. In other words, the presence of BRCA1 or BRCA2 mutations increases a woman’s chance of developing either or both cancers. According to the National Cancer Institute, a woman’s lifetime risk of developing ovarian/breast cancer is about 12 percent, compared to about 60 percent in women who have inherited the BRCA mutations. So women with the mutations are five times more likely to develop the cancers.
Yet, this really is a good example of where knowledge is power. If a woman tests positive, this information will help determine any preventative measures she may take in the future, from lifestyle changes to pre-emptive surgery.
It must also be pointed out that not all cancers are caused by genetics. There are other risk factors at play such as age, obesity, dietary fat and alcohol intake. See causes of cancer for more details.
The BRCA gene blood test is a DNA analysis used to identify the presence of either BRCA1 or BRCA2 gene mutations. This test is usually only offered to women with a family history of the disease. Genetic counselors are an important part of this process. In the initial meeting with your counselor they will assess if a test is needed, and if so, discuss the benefits and risks. They will arrange for blood to be drawn in a hospital or doctors office and then sent to a lab which specializes in genetic testing. The results usually take several weeks. When you return to your counselor they will give you the results and discuss the implications and options. It is important to note that Federal law ensures the privacy of all genetic information, so the results cannot be used to discriminate in employment or health insurance.
Who Is Offered A BRCA Test?
As of yet, there are no standard clinical criteria set for determining who should be tested for BRCA mutations. If there is a history of breast or ovarian cancer in the family, it may be recommended to go for testing. If the test proves positive for one person, the rest of the family may then go for testing. In practice, the following people are more likely to be recommended for testing:
• Premenopause women with a history of breast cancer: see breast cancer risk factors.
• Women who have a close relative who developed breast or ovarian cancer before the age of 50. More recently this has been extended to family incidences of fallopian tube cancer.
• Women with 2 or more close relatives who developed breast cancer (mother, sister, daughter). Or if one family member has had both breast and ovarian cancer.
• Women who have a male relative with breast cancer.
• Women with a family member with bilateral breast cancer.
• Women with 2 or more relatives with ovarian cancer.
• A relative has already been diagnosed with a BRCA1 or BRCA2 genetic mutation.
• Women with Eastern European Jewish ancestry (Ashkenazi) with a close relative who has had either breast or ovarian cancer.
What Do The Results Mean?
Positive Test Results
A positive test result means you have one of the potentially harmful BRCA genes. This does not mean you will develop breast or ovarian cancer, but it does mean that your risks are higher. Your counselor will discuss all your options and prevention measures, such as chemoprevention or even prophylactic surgery. See breast cancer prevention and preventing ovarian cancer for further details.
If the result is negative, it means that your likelihood of developing cancer is the same as the general population. However, where a woman has a history of close family members with the disease, and the results are negative, this can cause some uncertainty. This is because it is not clear if the test failed to detect the genes, or if she genuinely is free from the mutations.
One study showed that nearly 10 percent of women tested for BRCA ended up with ‘ambiguous’ results. This is where a change in their BRCA genes has been noted, but this change is neither standard nor linked with cancers in other people. In other words, scientists are not yet able to tell whether a person with uncertain results is more or less likely to develop cancer.
Benefits of Genetic Testing for Breast /Ovarian Cancer
There are benefits to receiving both a positive and negative results. A negative result will bring a sense of relief along with the possibility that preventive surgery or medications may not be necessary. A positive result can bring relief from uncertainty and allow women to take informed decisions about their future in the area of prevention. Many women with positive results choose to join health studies which help cancer research in the long run.
There is no physical danger to the woman with testing, as it only requires a blood sample. The risks rather are emotional, which is why genetic counseling is important. A genetic counselor can help a woman work through the issues raised by her test results. A positive result can make a woman anxious and depressed, particularly if preventative measures like prophylactic surgery is considered. Those who receive a negative result sometimes experience survivors’ guilt, knowing that they are less likely to develop cancer than loved ones. And for those with ambiguous results, no relief is given at all.
How Can I Arrange A Test?
The best way to arrange a test is through a genetic counselor. Your doctor should be able to recommend someone, or if not, you can contact the National Society of Genetic Counselors for a list of counselors: http://www.nsgc.org/
How Much Does A Test Cost?
The price of a BRCA test ranges between $300 to $3,500 depending on how extensive a test you choose. A limited test will only examine a few areas of the gene, whereas more extensive tests will examine hundreds of areas. Myriad Genetics, a molecular diagnostic company performs all commercial BRCA tests in the United States. Many insurance plans will cover the costs of genetic testing, so it is worth checking your details. Federal law prevents insurance plans from discriminating against an individual based on genetic information, so you should not be concerned. If you are, the other alternative is to pay yourself and submit your results under a code name.
Research: Ovarian Cancer Testing
According to the results of a survey which interviewed 1,900 American doctors, published in the Journal of Cancer (August, 2011), physicians are too quick to recommend expensive genetic testing or counseling for ovarian cancer to the wrong patients. Given a list of fictional patient descriptions 30 percent ended up referring women of average risk, although this is discouraged by strict guidelines. Yet, at the same time 60 percent did not refer those at high risk for the disease. As ovarian cancer is not very common, it occurs in 1 in 71 women compared to 1 in 8 for breast cancer - and there are no good screening tests - it is not usually discovered until it is too late. A small percentage of women are carriers of the BRCA1 and BRCA2 gene mutations which makes them a likely candidate for both ovarian and breast cancer. One company, Myriad Genetics charges $3,500 to test for the mutations but insist that patients usually only pay $100 out of their own pocket. As fewer than 1 in 300 women carry those mutations, this makes general screening too difficult and expensive. Instead, doctors are encouraged to follow guidelines, to learn the triggers and to better identify those at high risk.
BRCA Gene Testing Means Earlier Diagnosis
According to research from the The University of Texas MD Anderson Cancer Center (2011), breast cancer patients with BRCA gene mutations are being diagnosed 8 years earlier than previous generations. Given their greater risk for developing the disease, women with known mutation and/or whose mothers or aunts have the mutation are screened regularly from the age of 25. In 2007 the ACS recommended supplementing a mammography with magnetic resonance imaging (MRI) for this high risk category. An MRI is believed to catch smaller tumors even earlier. Many of the women are also offered prophylactic mastectomies as a part of their surveillance.