What if we could look into the future and know whether or not we’d someday fall victim to cancer? That’s essentially what newly developing genetic tests can do. While results do not provide an absolute guarantee of future health, they can help you and your relatives predict whether you are a likely victim of various […]
What if we could look into the future and know whether or not we’d someday fall victim to cancer? That’s essentially what newly developing genetic tests can do. While results do not provide an absolute guarantee of future health, they can help you and your relatives predict whether you are a likely victim of various diseases.
Mary Jo Tye, an elementary school principal, knows this first-hand. At 44, she was diagnosed with breast cancer. It was a shock – no one else in her family had ever had it. “When you look at family history, I did not fit the profile,” she says. Tye was fortunate: During her surgery to remove a quadrant of the breast, clean margins around the cancer were obtained, and all the cancer was contained.
“But I have a mother and a sister,” she says. “My cancer had huge implications for them.” And for her son, who might be at higher risk for prostate cancer or male breast cancer. “I always say knowledge is power,” notes Tye. So she decided to have genetic testing done.
“Scientists think there are 30,000 genes, although they are not sure how many are involved in cancer,” says Jenny Geurts, a certified genetic counselor for Aurora Health Care. But some genes have been unmistakably linked to breast cancer.
“The most common are the BRCA-1 and BRCA-2 genes,” notes Dr. Charles Bomzer, oncologist and director of the Familial Cancer Program, Oncology Alliance. “We look at mutations in those genes. If there is a mutation in one of the BRCA genes, women have a 40 to 70 percent lifetime risk of developing breast cancer.”
So Tye underwent a simple blood test to determine if her cancer would return and whether or not her family was also at risk. When her BRCA-1 and BRCA-2 genes came back clean, she breathed a sigh of relief. Not only could she be reasonably confident she would never have a reoccurrence of her cancer, she could abandon her fears for her family.
Genetic testing is a promising and fast-growing field, but it is still in its infancy. “I believe there will be a time,” says Bomzer, “when we will go to the doctor with a card recorded with our genetic makeup that will be put in a machine that predicts what our risks are and how we should modify our lifestyle.” But for now, you don’t always get conclusive answers. “It’s not a test that’s routinely given,” Bomzer adds. “A patient cannot go to a doctor and say, ‘I hear there is this gene out there. I want to get tested for it.’ ”
Instead, understanding what genetic testing really tells us requires enormous amounts of consultation time between patient and doctor. “We don’t have a crystal ball,” notes Geurts. “But we do have data and computer modeling to estimate risk. More awareness means we can be more proactive with screening and prevention.”
So currently, genetic testing is a tool, not an assurance of the future. And deciding who should be tested depends largely on personal and family history. Heredity plays a huge role. The first step is establishing the depth and width of family cancer, meaning you not only look up and down the family tree to parents and offspring, but out to siblings and cousins. The greater the incidence of familial cancer, the more likely genetic testing is in order. But who should be given the test is the big surprise. “The person tested should be the one affected by the cancer,” notes Bomzer, not the individual anxious to determine if he or she is a candidate.
Here’s why. What science is trying to do is search out the broken or mutated gene that has caused the cancer. If the answer is unknown, it may be a little like looking for a needle in a haystack. But if that gene can be identified within the relative who currently has the disease, then it opens the door for appropriate genetic testing of patients themselves for the gene conferring hereditary cancer.
There are, however, other circumstances when genetic testing of the patient is the proper course of action. If all family members are deceased, perhaps due to the cancer itself, then the only recourse is to test the patient. A simple blood test for BRCA-1 and -2 would be conducted.
Path to Treatment
Genetic testing is also applicable when determining how to treat a specific cancer. “Each tumor has a particular profile that has nothing to do with inheritance,” says Dr. Christopher Chitambar, an oncologist with Froedtert Hospital and professor for the Medical College of Wisconsin. “Each person’s cancer is different, and within their tumor there may be certain genetic abnormalities. Through a specific test called Oncotype DX, we look at 21 genes that have to do with certain characteristics of breast cancer. We come up with a score on a continuum. It is not an either/or situation.” So unlike a test for, say, diabetes, it’s not a question of simply being positive or negative.
“If the score is high, it means there is a greater chance a person will have a reoccurrence of the cancer,” notes Chitambar. “They may benefit from chemotherapy. If the score is low, they are less likely to benefit.” This is very good news for women desperate to avoid the often-brutal grind of chemo that can be routinely recommended.
But testing has huge psychological ramifications, notes Sara Svendsen, a certified genetic counselor with Froedtert Hospital and the Medical College of Wisconsin Cancer Center. “I don’t think most patients think about this prior to the initial consultation. They think it’s just a simple blood test.” But once patients learn they are at risk for a particular disease, they have to live with that information. That’s not always so easy.
“We lay out all the options to help them make a decision,” Svendsen adds. “We try to establish a plan of care for that patient, such as more frequent cancer screenings. Or they may choose to go through prophylactic surgery. If they are having trouble coping with the information, we will refer them to a therapist.”
But sometimes a little knowledge can be a dangerous thing. In a case where a patient has a very high risk of contracting breast cancer, for example, she may opt to have her breasts removed early in life. “However, we’re talking about the likelihood of developing cancer,” says Bomzer, “so a patient may go through mutilating surgery with no benefit. Or if ovaries are removed, you’re prolonging the length of menopause, which increases the risks for osteoporosis or heart disease. People think prophylactic surgery is easy and safe. But complications can occur. It is not a panacea. You may be trading one problem for another.”
What genetic testing can uncover is extensive. “There are hundreds and hundreds of gene tests available,” says Dr. David Bick, a genetics specialist and associate professor of pediatrics, obstetrics and gynecology with the Medical College of Wisconsin. Patients see Bick after discovering they’re pregnant or are contemplating becoming pregnant. Women over 35 years old may want information about the health of the fetus. But ethnicity is also a factor in the demand for prenatal testing.
“African-Americans are at risk for sickle cell anemia and may want to determine if they are a carrier,” he explains. “Caucasians carry a one-in-25 chance of carrying cystic fibrosis. Jewish patients may carry Tay-Sachs disease. Actually, there’s a panel of different hereditary conditions that apply to each ethnic group.” Prenatal genetic testing helps establish the likelihood parents will pass on these conditions to their offspring.
It’s the job of the geneticist to lay out the alternatives once results are attained. “The important thing is for [patients] to feel they have control and are making the decisions,” stresses Bick. “The geneticist should be nondirective by not bringing in their belief system. It’s wrong for a physician to impose their moral beliefs on a patient. After all, it’s the patient who has to live with the decision; the doctor just goes home.”
The ethical questions involved in genetic testing are no small matter. “What about someone who is adopted or whose mother used a sperm donor?” asks Bick. “Who has more rights? One of the great debates that’s going to play out is, once you get genetic information, to whom are you responsible? If you find out something that could affect your children or your sister, should you tell them?”
Clearly, genetic testing raises tremendously sensitive individual and societal issues. But it also has enormous power to revolutionize the field of cancer prevention and care. And it’s sure to remain a hot topic as scientists and medical professionals discover more about this new inner frontier. n
Janine S. Pouliot is a frequent contributor to Milwaukee Magazine.
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