I just recently became aware of a 2014 report on a 25-year
study involving almost 90,000 Canadian women to determine the benefits of
mammograms. The researchers wanted to know if there was any advantage to
finding breast cancers when they were too small to feel. The answer was no.
They also found that screening with mammograms can be
harmful. One in five cancers found with mammography was not a threat to a woman’s
health, yet the women received unnecessary chemotherapy, surgery, and/or
radiation.
Approximately half the women were assigned to have regular
breast exams by trained nurses, and half were given regular mammograms in
addition to the breast exams.
At the end of the lengthy study, the number of women who
died from breast cancer was 500 among those who had mammograms, and 505 among
those who did not.
A quote from a NY Times article about the study: “Many cancers, researchers now recognize,
grow slowly, or not at all, and do not require treatment. Some cancers even
shrink or disappear on their own. But once cancer is detected, it is impossible
to know if it is dangerous, so doctors treat them all.”
This reminds me of something I once read about prostate
cancer—that it’s unwise for men to be screened at too early an age because
screening is likely to pick up cancers that will grow so slowly that they’ll
never become a problem.
In Switzerland, the Swiss Medical Board has advised that no
new mammography programs be started, and that those already existing be limited in duration. One member of the Board said mammograms were
not reducing the death rate from the disease, and they led to false positives
and needless biopsies.
Mammograms are big money-makers. In the U.S., about 37 million
mammograms are performed annually at a cost of about $100 per mammogram. I
guess it’s not surprising that although the results of the Canadian study came
out last year, mammograms are still promoted in the U.S. as far as I can tell.
In discussing the potential harm done by mammograms, I have
to mention radiation. My only known risk of breast cancer is from having my
adenoids removed via radiation when I was 6 years old. It has never made sense to me to expose myself
to more of it, so I’ve had only two mammograms in my lifetime.
Another quote, this one from Dr. Russell P. Harris, a screen
expert and professor of medicine at the University of North Carolina at Chapel
Hill: “The decision to have a mammogram
should not be a slam dunk.”