DeCode Genetics has announced that it will begin selling a new genetic test that, it says, can assess a womanâ€™s lifetime risk of developing the most common types of breast cancer. Currently, genetic testing is primarily used in women with an extensive family history of breast and ovarian cancer to see if they carry one of the breast cancer genetic mutations, called BRCA1 and BRCA2.
These mutation accounts for about 5 percent of all breast cancer cases. But women who have the BRCA1 or BRCA2 genetic mutation have up to an 85% chance of developing breast cancer. In contrast, the average lifetime risk for a woman of European descent is about a 12%.The new DNA test, called deCode Breast Cancer, is performed on a blood sample or a cheek swab. It must be ordered by a physician for their patient. (A woman canâ€™t order it directly from the company herself.)
The DNA test measures seven genetic variations (SNPs; pronounced â€œsnipsâ€) in the human genome that have been linked to breast cancer risk. The result is given as a numerical â€œscoreâ€ that represents your personal lifetime risk of developing breast cancer.The test costs $1,625 dollars. It is not yet known which, if any, insurance companies will pay for it. Only deCode can perform the test, and they do this at their lab in Illinois. Currently, genetic tests that are performed by a single laboratory donâ€™t have to be approved by the FDA before they can be sold in the U.S. This means the FDA has not reviewed any data about the test, and that it will not regulate how the test is done. Because it is a genetic test, deCode does not take into account other known risk factors, such as family history of breast cancer in close relatives, age at first menstrual period, pregnancy history, and breast density. These are the risk factors that are currently used to assess risk and to determine if a woman is at higher than average risk. This risk is typically determined with a tool like the Gail risk calculator. The deCode test will probably identify some women who would be missed by the Gail calculator. But we donâ€™t have any idea how many.
If you have the test done, and find you are at higher than average risk, what can you do? Thatâ€™s the real question we face at this time. Women who have a BRCA mutation have a risk as high as 85% of developing breast cancer, and all we can offer them is intensive surveillance or surgery to remove their breasts or ovaries before a cancer diagnosis. Currently, the American Cancer Society recommends that women who have a lifetime risk of 15-20% or higher have annual MRI screening in addition to mammograms. While this is still quite controversial, women who are found to be high risk based on a deCode test might consider adding an annual MRI to the annual mammogram. Another option might be chemoprevention with the drug tamoxifen.
The bottom-line: The test can tell you if you are at higher than average risk of getting the most common types of breast cancer. However, if the test is negative you can still get breast cancer and if it is positive you may not get the disease.So, at the end of the day, thereâ€™s not a lot that you can do with that information. Right now, most women who learn they are high risk on the Gail model donâ€™t choose to take tamoxifen because they donâ€™t want to take a drug that has many side effects to try to prevent a disease they may not get. Would a genetic test result make a woman more likely to use this drug? We donâ€™t yet know.Undoubtedly, this is the first of many tests we will be seeing that use genetic information to assess breast cancer risk. If anything, it underscores why we need to change our focus from trying to find breast cancer early to learning what causes it and how to prevent it in the first placeâ€”which is precisely what the Love/Avon Army of Women is going to do.You can learn more about the Love/Avon Army of Women, my revolutionary new initiative to end breast cancer, here.