HOME DNA TESTING FOR BREAST CANCER: WHAT YOU NEED TO KNOW
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Healthcare professionals are glad that a growing number of people want to learn more about their genetic makeup and how it might affect their health. What worries them is if people are learning enough.
Ryan Bisson, a cancer genetic counselor with Orlando Health, had a mixture of thoughts about the announcement that the US Food and Drug Administration had approved 23andMe’s first direct-to-consumer test that detects some DNA mutations associated with breast cancer.
“It was big news in the genetic counselling community,” he said. “The immediate impact is that consumers can skip over the geneticist and go straight to the lab.” Understanding what those lab results mean, however, “becomes a trickier situation.”
That sentiment was echoed by the president of the National Society of Genetic Counselors, Erica Ramos, who issued a statement in reaction to the FDA announcement, warning that “although this test may help to identify people who have a previously undetected BRCA mutation, there are several limitations and the results may be confusing or misleading without appropriate education.”
The test is provided by 23andMe, a personal genomics and biotechnology company that has been marketing direct-to-consumer tests for years. The company’s saliva test provides its customers with all sorts of information about their genetics, some seemingly trivial, and some serious. The company is now allowed to tell its customers if they have any of three BRCA gene mutations that are found most commonly in people of Ashkenazi Jewish descent, and that are associated with an elevated risk of breast and ovarian cancer.
Although breast cancer is common, only five percent of breast cancer is hereditary. Normally, the BRCA genes function as safeguards against cancer and are called “tumor suppressor genes.” They protect cells from growing out of control and developing into the disease. A mutated BRCA gene – though rare among the general population – can sharply increase cancer risk.
The 23andMe test only screens for three out of over 1000 possible BRCA gene mutations. Although the BRCA genes are the main genes associated with hereditary breast cancer, there are many other breast cancer genes. Therefore, a family may still have a hereditary form of breast cancer even if they were not found to carry a mutation by the 23andMe genetic test.
But testing positive or negative for certain mutations is just one of several cancer risk factors – personal and family history, ancestry, lifestyle, and environment all play roles. It is the job of a genetic counselor to work with patients to review all of these factors.
Since the patient’s health care provider is not involved in the ordering of direct–to–consumer genetic testing, other cancer risk factors may be ignored. Genetic counselors interview patients, discuss their family histories, calculate their cancer risks and then, if they are suspicious of a genetic factor, discuss testing. Sometimes it may be more helpful to begin with genetic testing of other family members, a mother or aunt, for instance, before testing the patient. The role of the genetic counselor is to help the patient make informed decisions.
There is a concern that some consumers may regard a negative genetic test result as a clean bill of health, or they may regard a positive one as a need for aggressive intervention. Without proper counseling, either reaction could have serious repercussions. We have had patients state that “I will get genetic testing and if the results are normal, I will not have to undergo mammographic or other breast cancer screening” stated Dr. Rebecca Moroose, medical director of the Cancer Genetics and High Risk Center at Orlando Health UF Health Cancer Center. “This is a very uninformed response as 90 – 95% of breast cancers are not related to an inherited mutation.”
The role of genetic counselors in the medical community is small but growing. Orlando Health, for example, has eleven genetic counselors on staff, specializing in cancer, prenatal care and pediatrics.
The Cancer Genetics Center at Orlando Health UF Health Cancer provides information that will help patients understand their risk of developing breast cancer and identifies those who may be at high risk for hereditary forms of the disease.
Anyone interested in learning more about genetic testing and counseling is invited to attend a free educational event featuring genetics specialists from Orlando Health UF Health Cancer Center. The program, led by Dr. Moroose and Mr. Bisson, will discuss the latest advances in genetic testing, how genetic testing can determine one’s risk for cancer, and more.