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A National Dialogue on Genetic Testing for Breast Cancer

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A high-profile case of a medical decision being based primarily on the results of a genetic test has prompted a national discussion on the benefits and risks associated with acting on the results of such a test.

Ellen T. Matloff, MS, CGC

When actress and director Angelina Jolie announced that she had undergone a preventive double mastectomy, she said the decision was based on the results of genetic testing that showed she had an 87% chance of developing breast cancer based on a mutation in the BRCA1 gene, which, along with mutations of the BRCA2 gene, are closely associated with development of the disease.

This high-profile case of a medical decision being based primarily on the results of a genetic test has prompted a national discussion on the benefits and risks associated with acting on the results of such a test.

Some insight is being provided by a genetic counselor who recently conducted a survey of her peers, asking how they would bring their knowledge and experience with BRCA mutations to bear if they found they had one themselves.

According to the National Cancer Institute (NCI), women who inherit harmful BRCA1 and BRCA2 mutations are five times more likely to develop breast cancer over the course of a lifetime, and they are also at higher risk of developing early-onset breast and ovarian cancer. Additionally, the NCI estimates that moderate- and high-risk women who undergo a preventive mastectomy may reduce their chances of developing breast cancer by as much as 90%, according to existing data. However, the NCI does caution that this may not guarantee a woman’s protection from ever developing breast cancer.

According to the NCI, women who test positive for a harmful BRCA1 or BRCA2 mutation also have a wide range of options that do not involve prophylactic surgery, including surveillance, risk avoidance, and chemoprevention. In the case of chemoprevention, taking drugs such as tamoxifen or raloxifene may reduce the risk of developing breast cancer.

A preventive mastectomy is something that genetic counselors are warming up to more so than they were 15 years ago, according to the survey of 216 active members of the National Society of Genetic Counselors’ Special Interest Group in Cancer. The survey found that 58.3% of genetic counselors would opt for bilateral prophylactic mastectomy if they tested positive for a deleterious BRCA mutation at age 35 (Jolie is 37). In 1998 when genetic counselors were asked the same question, only approximately 25% said they would opt for the surgery under the same circumstances.

“Having genetic testing was really something that people did under an alias,” said Ellen T. Matloff, MS, CGC, Certified Genetic Counselor and director of the Yale Cancer Genetic Counseling Program at Yale Cancer Center in Connecticut, who conducted the study. “They were afraid to bill their insurance companies. If they did have genetic testing, they were afraid to share this information with their physicians or even with family and friends, and we know since then that many more people are open to genetic testing.”

Matloff explained that a couple of factors contributed to these favorable trends in genetic testing. More studies supported the efficacy not only of genetic testing but of prophylactic bilateral mastectomies, showing that these steps did reduce the risk of developing breast cancer. Additionally, Matloff said that genetic counselors gained more clinical experience so that they could see how patients would react to the results of genetic testing and how it could impact not only the way they were treated but also how they dealt with the psychosocial impact of a cancer diagnosis at a genetic level.

With regard to Jolie’s decision, Matloff said the 87% risk that the actress quoted in her piece for The New York Times could be a little misleading. At Yale, Matloff said she gives patients a range of their risk based on the findings of genetics tests, such as 50% to 85%.

“Quite frankly, that’s as accurate as we can get right now,” Matloff said.

External Resources

Angelina Jolie announces that she underwent a preventive double mastectomy after discovering she had an elevated risk for developing breast cancer. nytimes.com.

CBS News covers Angelina Jolie's decision to undergo a double mastectomy, and Patrick I. Borgen, MD, chair of the department of Surgery at Maimonides Medical Center in Brooklyn, New York, and one of the program directors of the Miami Breast Cancer Conference, offers his thoughts on mastectomies. cbsnews.com.

Matloff said that when patients learns of their risk for a particular cancer based on genetic testing, they should meet with a genetic counselor and map out where they are in their lives, how much they worry about their cancer risk on a daily basis, how well they tolerate surveillance, and what decisions they would plan on making should they receive a diagnosis of cancer, as these can all affect the course of treatment patients receive.

In a statement, Otis W. Brawley, MD, chief medical officer for the American Cancer Society, echoed Matloff’s thoughts, stating that patients need to be able to discuss options with genetic specialists and health professionals in order to make a decision that’s appropriate for them.

“This does not mean every woman needs a blood test to determine their genetic risk for breast and/or ovarian cancer,” Brawley wrote. “What it does mean is women should know their cancer family history and discuss it with their regular provider. If appropriate, they should be referred to and have the opportunity to discuss their risk and their options with a genetic specialist.”

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