Genetic Test Could Tell People Who are High-Risk for Breast Cancer

PJ Hamel Health Guide June 29, 2008
  • If a simple test could tell you, at age 18, whether you were at high risk of developing breast cancer at some point during your lifetime, would you take the test? 

    If you took the test, and the results said yes, you’re at increased risk—what would you do? Change your lifestyle? Your eating habits? Have a double mastectomy?

    How would you feel? Terrified? Empowered?

    The New England Journal of Medicine reported last week that scientists are probably “just a few years away” from a simple, inexpensive genetic test that could determine who among us is most likely to get breast cancer.


    Currently, there are two known genes—BRCA1 and BRCA2—that have been identified as increasing a woman’s risk. But they’re very rare, confined to a small percentage of the population.

    Recently, seven new genes directly related to breast cancer have been discovered; and researchers are assuming that this opens the door to many more women finding out they’re at increased risk. There’s been a torrent of questions generated by this discovery; and cancer specialists around the world have spoken out, calling for caution and further research before the widespread use of such a genetic test becomes the gold standard of prevention.

    First, genetics isn’t the only factor in who gets breast cancer. In fact, it’s not even the most important one. Commented Professor Graham Giles, of Australia’s Cancer Epidemiology Centre, "There are women who will be deemed high-risk and will never develop breast cancer and there will be women deemed low-risk who will get breast cancer because genes are not the only determinants of cancer." Added Dr. John Boyages of Australia’s New South Wales Breast Cancer Institute, "They have now found seven genes linked to breast cancer but there could be 27 that we don't know about yet, so [a test result showing low risk] gives women false reassurance."

    But say you took the simple mouth-swab test, and you were negative for these genes. Would you be tempted to breathe a sigh of relief, assuming you were home free, and never get another mammogram? Ignore any breast changes?

    Or what if you were identified as being at high risk? Breast cancer in younger women isn’t easily diagnosed via mammogram, due to higher breast density. Would you want a regular (expensive) MRI (which is notoriously prone to many false-positive results)? Would you be compulsive about feeling for lumps? Would the fear of cancer begin to rule your life? As Dr. Boyages said, "And what does a 20-year-old girl do when she tests positive? Takes both her breasts off?"

    What if you tested “part-way positive”—not at high risk, not at low? Should you worry? How much? Have mammograms? How often?

    There are no doubt women who would handle their test results responsibly and well, whether they were shown to be at high risk, or no risk. High-risk women who’d be vigilant without panicking. Low-risk women who’d continue to pursue a healthy lifestyle and report breast changes to their doctor.


  • But I’m sure there’s a whole middle ground of women who wouldn’t handle their test results well at all. Women who’d be terrifically, chronically stressed by the news they’re at high risk. Women who’d assume their low-risk result gave them the go-ahead to eat, drink, and be merry for the next 30 years.


    Think about it. Are you sure you want to get a glimpse of the future, knowing that what you see may be a killer within you, one that may remain silent forever… or not?

    Food for thought.