Genetic counselor Shelly Cummings, MS, stresses that it's very important to understand and carefully weigh the pros and cons of genetic testing before going ahead with it. About a quarter of the women diagnosed with breast cancer have some family history, but the specific DNA changes linked to breast cancer are much less common that that (accounting for only about 5% to 10% of all breast cancers) . . . and far more likely to trigger illness.

So who should be tested for altered breast cancer genes? What can a woman with positive test results do to stay healthy? Should women (and men) with the altered genes have children?

Cummings answered these, and other common questions, based on her experience as Assistant Director of the Cancer Risk Clinic at the University of Chicago Medical Center.

Who should be tested for genes changes that cause breast cancer?

"A woman should consider genetic testing for changes in the BRCA1 and BRCA2 genes if she has a family history of multiple individuals with breast cancer from different generations. We take a three-generation family history [for women who come in for counseling] and in most families we can see a pattern of breast cancer . . . although not always."

"Women who've have the disease themselves, particularly at a young age, could consider being tested, too. Even though they might not have seen a family history of breast cancer, because they have a small family."

Other factors that increase a woman's risk for breast cancer and should be discussed during genetic counseling include:

• Having two or more relatives with breast or ovarian cancer.
• Breast cancer before age 50 in a relative (mother, sister, grandmother or aunt) on either side of the family. The risk is higher if your mother or sister has a history of breast cancer.
• Relatives with both breast and ovarian cancer
• One or more relatives with two cancers (breast and ovarian, or two different breast cancers)
• A male relative (or relatives) with breast cancer
• A family history of breast or ovarian cancer and Ashkenazi Jewish heritage
• A family history that includes diseases associated with hereditary breast cancer, such as Li-Fraumeni or Cowdens syndromes

Cummings warns that, on occasion, hereditary breast cancer can appear to skip a generation, giving family members the mistaken idea that there's nothing to worry about. "When families see that the mother didn't have it, though the grandmother did, they think they're safe, but they may not be."

What will I learn from being tested?

"Some women think the test can tell them when they will get cancer, and of course it can't. If they think it's like a cholesterol test with an exact number, they've got the wrong idea—there's a lot of gray area [in how genes influence woman's individual risk of breast cancer.]

"We believe that the lifetime risk of developing breast cancer among women with altered BRCA1 or BRCA2 genes ranges from about 40% to as high as 85%. Those numbers are based on multiple studies, and the 85% risk estimate comes from four to five studies of breast cancer found at an early age. Mutations in these genes also increase your risk for ovarian cancer by up to 60%."

"Eastern European women with the altered genes have a 56% lifetime risk of developing breast cancer. There are many different mutations that can occur on these genes . . . . Some preliminary papers indicate that women with a BRCA1 mutation have a more aggressive cancer in which the cells are dividing rapidly."

If testing shows I have an altered gene and a very high risk for breast cancer, what should I do?

"Before having the test, women need to be fully informed about what their options will be afterward . . . and they need to decide what they're going to do. What will they do if the test results are positive? What if they're negative?"

"If you have this history of cancer and you don't want to have preventative surgery or do anything different than continue being followed carefully for early signs of breast cancer, then why do you want to take this test?"

"Most women want to know their risk; whether they'll pass it on to future generations. [But even when] two women share the same level of risk, they can have very different ideas about what it means and make different decisions about what to do after testing."

The options for women who have inherited an altered BRCA1 or BRCA2 gene include earlier, more frequent screening for signs of cancer with mammograms, breast exams, possibly breast MRI scans, and ultrasound exams of the breasts and ovaries. Tamoxifen and certain other drugs may help reduce the risk of breast cancer. Prophylactic (preventative) mastectomies and surgery to remove the ovaries are proving to be effective in greatly reducing the risk of cancer in very high risk women, and women can join a research study of new therapies.

"For some individuals, it really takes something strong, like an altered gene, to get them to do something about their personal risk," Cummings added.

Who will have access to my test results? Can they be used to deny me life and health insurance, or increase my premiums?

"Patients have an exaggerated fear [that genetic testing results will fall into the wrong hands and they won't be able to get insurance]; the reality is it's not happening, or at least we're not hearing about it. Their fear is greater than the risk. But we do need a better federal law."

How will my blood test for altered breast cancer genes affect my family?

"This is a genetic test. It's going to tell you what's passed down through the family and if you have the gene, that means one of your parents has it, too, and your sisters, brothers, and children could also have inherited it. It becomes an ethical question. Do they want or need to know? Should you tell them?

"Because it can have come down multiple generations, then cousins, aunts, all those people can be at high risk."

Should people with the gene mutations have children?

"It's a personal decision. Your daughter could be the first woman president. Breast cancer is a highly treatable disease. There are a lot of women who have it and go on to have productive lives."

"In our practice, after people were educated about [the ramifications of having changes in BRCA1 and BRCA2], the benefits of having children seemed to outweigh the concerns."

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