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Monday, November 29, 2010

Getting tested for BRCA genes

I have been asked many times whether to be tested for the gene mutations which increase risks of breast cancer, also known as BRCA genes. There are a few such gene forms identified, which together account for a large percentage of hereditary breast cancers, as discussed in this National Cancer Institute fact sheet. These genetic mutations code for faulty enzymes responsible for repairing damage to DNA that causes cancer.

The first question in deciding whether or not to get tested is whether you have had breast cancer!! If so, get tested!! If you are positive for one of the BRCA mutations, it should have a big impact on whether you decide to have a prophylactic, that is, preventive mastectomy of the other breast. Women without BRCA mutations do not survive longer if they have second mastectomies. It also affects how frequently you screen the other breast with a mammogram. I am always surprised by how many people (yes, men get it too) who have had breast cancer have not had these genetic tests! This is a situation in which the downsides are much fewer. Specifically, the documentation of increased risk which might make it hard to get health insurance, is besides the point, since the history of breast cancer already confers that risk.

If you haven't had breast cancer yourself, the next question is if you know the medical history of your first degree female relatives, your mother and your sisters, or your father's sisters and mother. If you do not, consider whether you are in one of the ethnic groups at higher risk of the genetic mutations which increase the risk of breast cancer (Ashkenazi Jews, Icelanders, Norwegians, and Dutch). If you are in one of these ethnic groups, and you don't know your personal family history, you are likely to benefit from being tested.

If you do know your mother's, your sisters', both of your grandmothers' and your father's sisters' medical histories, and know what they died of, and they lived into their older years (70s or 80s, say) without developing breast cancer, then there is little chance that you have an extra genetic risk of breast cancer. Your lifetime risk is then like the risk in the general population without a family history of breast cancer, or about 12%, and there is no special reason to be tested.

Now, if your mother or sister did get breast cancer, is there any additional advantage in getting tested for BRCA genes?

The first step is, if the person who had breast cancer is still alive, to ask that person if they were tested for these gene mutations. If they were not, you could ask if that person is willing to be tested. The reason is that if they are negative for one of the gene mutations, then you are unlikely to have an increased risk on that basis too, and testing is much less helpful and not recommended. The second reason is that if they are positive, and you then get tested and test negative, you can set aside worrying about increased risk due to your family history as you have probably not inherited that risk.

If the person in your family who has breast cancer has died or refuses to be tested, the pros of getting tested are that if you test negative, you can get screened less often than if you are positive. If you are positive, you can get screened more frequently, and using different forms of screening such as ultrasound. Also, if you are positive, you can get screened for ovarian cancer, which is not normally done otherwise, because women with BRCA genes have increased risk of ovarian cancer. You may also wish to have prophylactic bilateral mastectomies, or if you develop cancer, to get the other breast removed at the same time. The lifetime risk of developing breast cancer when one is identified as being at genetic risk is extremely high, and many women opt for this solution, even some without BRCA genes. Finally, as above, if you do develop breast cancer, evidence has shown that if you do not have a BRCA mutation, having a prophylactic second mastectomy does not improve your survival.

The biggest downside of testing for breast cancer risk genes is being identified by insurers as being at increased risk. While there is now a federal law against insurers discriminating against women on this basis, this is totally unenforceable. Women can be denied by insurers for a host of spurious reasons (one woman I know was denied because she had had a urinary tract infection treated with antibiotics in the last year!) which may be cover-ups for other risk factors. We also have no assurance that health care reforms banning exclusion of pre-existing conditions or refusal to insure people with those conditions, will remain after future changes in the political landscape. Many women will feel with some justification that it is simply better not to have this risk recorded.

The solution to this downside, of course, is to get tested anonymously outside the insurance system. Then, at least, you will not be classified as being at extra risk unless you divulge this information to a physician because you wish to do something about it (such as bilateral mastectomies). Most labs will send specimens anonymously as long as you are paying for it and not the insurance company. Now that the patent on the BRCA1 gene has been struck down, other companies besides Myriad Genetics will spring into the marketplace and testing is likely to become less expensive. This brings up a new downside: the cost of testing, which depending on how many genes are tested for, can be anywhere from a few hundred to a few thousand dollars. See this discussion in the National Cancer Institute's factsheet

Getting tested may cause other harm worth mentioning. The increased screening for breast cancer which you are likely to have if you test positive carries risk. If you get screened more, you are more likely to have a false positive mammogram, or ultrasound, or breast MRI, with unnecessary biopsies, etc. Radiation from mammography and MRIs may also cause some increased risk. There has been a lot of recent publicity around why one might want to avoid mammography and screening despite a family history of breast cancer such as this recent column in Health Affairs.

The organization Facing Our Risk of Cancer Empowered (FORCE) runs a hotline to help answer questions about breast cancer risk and screening for breast cancer genes. Local communities often have support networks as well. In Palo Alto, there is also an organization called Breast Cancer Connections which specializes in helping newly diagnosed women, but also provides a lot of information to women about risks for breast cancer.

For additional information, ask your doctor to refer you to a genetic counselor. You can check with your insurance about whether they cover a visit like this. They may only do so if you have a family history of breast cancer.

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