Anne is a good
patient. She sees her doctor for regular checkups, has yearly mammograms,
Pap tests, and colon cancer screenings, and she even paid for a
full-body CT scan out of her own pocket. She figures she’s doing
everything she can to make sure she doesn’t get cancer.
Truth is, Anne
is doing nothing to prevent cancer. Although cancer screening is
billed as a preventive service that saves lives, the best it can
do is detect disease in its early stages, when it is supposedly
easier to treat. Nevertheless, every year millions of Americans
dutifully line up for their screenings, completely unaware that
they may be doing more harm than good.
For more than
15 years, I’ve been warning patients about the downside of mammograms,
PSA testing, and the overall concept of cancer screening. It hasn’t
been a popular position. Today, however, there’s a small but growing
band of researchers, clinicians, and expert panels who are speaking
out against the unbridled use of these tests. One of them, H. Gilbert
Welch, MD, a professor at Dartmouth Medical School, has laid out
very persuasive arguments in an aptly titled book, Should
I Be Tested for Cancer? Maybe Not and Here’s Why. In this
straightforward and well-referenced book, Dr. Welch raises several
concerns about cancer screening.
1. Few People
Benefit From Screening
the majority of folks who are screened receive no benefit. That’s
because, despite scary statistics, most people will not get cancer.
Let’s look at breast cancer as an example.
government statistics, the absolute risk of a 60-year-old woman
dying from breast cancer in the next 10 years is 9 in 1,000. If
regular mammograms reduce this risk by one-third – a widely
cited but by no means universally accepted claim – her odds
fall to 6 in 1,000. Therefore, for every 1,000 women screened, three
of them avoid death from breast cancer, six die regardless, and
the rest? They can’t possibly benefit because they weren’t going
to die from the disease in the first place.
worked as touted, death from breast cancer would be rare, since
three-quarters of American women 40 and older get regular screenings
(a total of 33.5 million per year). The modest decline in the death
rate from the mid-1970s, when mammography was introduced, through
the present can be attributed to factors other than screening, such
as changes in treatment and the dramatic decrease in the use of
Premarin and other cancer-promoting hormone replacement drugs. It
doesn’t take a rocket scientist to figure out that mammograms do
not substantially reduce risk of death from breast cancer.
2. The Most
Deadly Cancers Are Missed
The flip side
is that some people who are screened get cancer and die anyway.
Test results aren’t always accurate. Sometimes cancer is there,
but it’s missed (false negatives). In the case of mammograms, it
could be a question of a poor-quality test or a radiologist who
overlooked something. Even experienced radiologists don’t always
interpret test results the same, and sometimes they just plain get