Testing for Breast Cancer Gene: No Simple Answers

A genetic mutation can significantly increases a woman’s risk of developing breast cancer and ovarian cancer. But does that mean everyone should be tested?

A new direct-to-consumer advertising campaign in select markets nationwide urges women to get tested. But experts from the University of Michigan Comprehensive Cancer Center warn that the test is not appropriate for all women.

“While the test is a very easy thing to do - it’s a simple blood test - the interpretation of the results can sometimes be very complicated,” says Mark Pearlman, M.D., vice chair and professor of obstetrics and gynecology at the University of Michigan Medical School.

In fact, experts estimate only 2 percent of the population should be tested for these mutations, which occur in genes called BRCA1 or BRCA2.

Women who inherit a mutation in these genes face a higher lifetime risk of developing breast and ovarian cancer, and cancer is more likely to develop at an earlier age. Lifetime risk of breast cancer in these women jumps from 12.5 percent in the general population to approximately 60 percent in women with BRCA mutations. Lifetime ovarian cancer risk rises from 1.4 percent up to 40 percent for those with the mutation.

But most breast and ovarian cancers are random, and are not linked to the BRCA genes. Fewer than 10 percent of all women with breast cancer carry one of the BRCA gene mutations and about 15 percent of women with ovarian cancer carry one of the mutations.

“It’s very important that the right women seek out genetic testing for breast and ovarian cancer,” says Sofia Merajver, M.D., Ph.D., director of the Breast and Ovarian Risk Evaluation Program at the University of Michigan Comprehensive Cancer Center. “Cancer risk is more complex than a simple yes or no, and the test for genetic mutations is only part of the picture.”

Women who seek genetic testing should work with a genetic counselor and a physician who is specially trained to help people understand what their test results mean for their cancer risk – and what they can do to reduce that risk.

“Working with a genetic counselor, somebody who understands genetics, is very important because a positive test has a plan that has to go with it. At the same time, a negative test doesn’t always mean that person is no longer at risk. So getting the test results back without any other knowledge and without any other information is potentially dangerous,” Pearlman says.

Pearlman and Merajver work together at the U-M Comprehensive Cancer Center to manage women who are seeking or have undergone genetic testing for breast and ovarian cancer, educating women and their families through genetic counseling and providing prevention, risk management and coping strategies for women who test positive.

“It’s important to understand that getting the genetic test result is only a piece of the puzzle. It really takes a professional who understands genetics to help work with individual women and men to allow them to understand exactly what that piece of information means to them in terms of their risk, their loved ones’ risks and what can then be done to help lower that risk,” Pearlman says.