Genetic tests pose opportunites, dilemmas for patients
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Marla Dansky is scheduled for two rounds of surgery this summer, shortly after she completes chemotherapy treatments for a tumor in her left breast.
Her first operation at Duke Cancer Center will remove both breasts. A second will take out her ovaries and uterus, which are not cancerous but are likely to develop the disease, based on genetic tests that show she carries a faulty BRCA1 gene.
"It's the best pre-emptive strike that I have," Dansky, 40, said of her decision to undergo a complete hysterectomy in addition to bilateral breast surgery. "My plan is to 'do cancer' once, and do it right the first time."
The strong link between the BRCA1 gene and cancer, as well as the option to sidestep much of the risk through elective surgery, grabbed headlines recently when actress Angelina Jolie made public her decision to undergo a double mastectomy.
But the procedure isn't only available to movie stars. More than a third of women who test positive for BRCA1 are choosing preventive surgeries — largely because the gene mutation raises the typical 10 percent risk of female breast cancer to something closer to 80 percent, according to the National Cancer Institute.
Screening for breast cancer is now one of more than 1,000 genetic tests available to evaluate health risks. Such tests offer unprecedented opportunities to take steps to avoid serious illness in many cases, but they pose dilemmas for patients facing a high risk for diseases with no known cure.
Individuals seeking more general clues to their genetic profiles, for example, are turning to direct-to-consumer testing companies. A number of companies offer to scan blood or saliva samples for indications of risk for common diseases such as macular degeneration or diabetes, as well as more serious conditions such as cancer or Parkinson's disease.
One such testing company, the Web-based 23andMe, evaluates genetic indicators for health, ancestry and other traits using saliva samples sent in by customers, said company spokeswoman Catherine Afarian.
In 2007, when the testing was first offered, the service produced 14 reports for $999. Now more than 240 reports are available for $99, Afarian said.
"It's a reflection of the amount of research that is being done in the field of genetics," she said.
Kristy Lee, a certified genetic counselor at the University of North Carolina Cancer Center, said she has counseled patients who have had difficulty interpreting their commercially obtained results. Some seem overly frightened by slight elevations in risks with little statistical significance, while others are shocked to learn they may someday face serious disorders with no known treatment.
"I don't think people understand the gravity of the information they can get," Lee said. "While a lot of the direct-to-consumer testing is just fun stuff, like ancestry or whether you like Brussels sprouts, the medical stuff, which looks at a bunch of markers across different genes, can be easily misinterpreted."
When an oncologist suggested to Dansky that she consider preventive surgery after her mother and two aunts were diagnosed with breast cancer, she was resistant. But after mammogram revealed a tumor, and a biopsy confirmed that it was cancer, Dansky began to soften. First, however, she underwent genetic testing that confirmed the BRCA1 gene.
"Because my ancestry is Ashkenazi Jewish, I wasn't really surprised by the results," she said.
In the overall population, BRCA1 and 2 mutations occur in 1 in 500 people. For some specific groups, however, the odds are much greater, among them descendants of the Ashkenazi Jews of Eastern Europe, who have a 1 in 40 chance of having a BRCA1 mutation.
Tests to determine BRCA mutations were developed in the mid-1990s and have been in widespread use by oncologists since the early 2000s, with other physicians joining over the past five years.
In some ways, the availability of genetic testing may be running ahead of the curve of medical practice. And there are issues of privacy. The federal Genetic Information Nondiscrimination Act prevents health insurance companies from denying health coverage based on genetic test results. But other areas such as employment law and life insurance coverage have not yet been addressed, said John Evans, professor of genetics and medicine at UNC.
Evans and Andrew Olshan, an epidemiologist at the UNC Gillings School of Global Public Health, co-authored an article in a recent edition of Genetics in Medicine calling for more research into the best way to incorporate genetic screening into medical practice, along with public policies to maximize benefits and manage costs.
Their proposal stresses the need to target serious diseases that may be prevented, treated or cured based on genetic information. Colorectal cancer, breast cancer, hereditary heart disease, thyroid cancer and certain types of aneurysms are among them.
"The underlying concept is that people are walking around carrying mutations that dramatically predispose them to severe diseases that are entirely preventable if you know about them," Evans said. "Without genetic testing, you are just waiting for someone in your family, or you, to develop one of these diseases."
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