Overdiagnosis and overtreatment


Vast Study Casts Doubts on Value of Mammograms
by Gina Kolata
New York Times, 2012-02-12

One of the largest and most meticulous studies of mammography ever done,
involving 90,000 women and lasting a quarter-century,
has added powerful new doubts about the value of the screening test for women of any age.

It found that the death rates from breast cancer and from all causes were the same
in women who got mammograms and those who did not.
And the screening had harms:
One in five cancers found with mammography and treated
was not a threat to the woman’s health
and did not need treatment such as chemotherapy, surgery or radiation.

The study, published Tuesday in The British Medical Journal,
is one of the few rigorous evaluations of mammograms
conducted in the modern era of more effective breast cancer treatments.
It randomly assigned Canadian women
to have regular mammograms and breast exams by trained nurses
or to have breast exams alone.

Researchers sought to determine
whether there was any advantage to finding breast cancers
when they were too small to feel.
The answer is no, the researchers report.

The study seems likely to lead to an even deeper polarization between
those who believe that regular mammography saves lives,
including many breast cancer patients and advocates for them,
and a growing number of researchers who say
the evidence is lacking or, at the very least, murky.

“It will make women uncomfortable, and they should be uncomfortable,”
said Dr. Russell P. Harris, a screening expert and professor of medicine at the University of North Carolina, Chapel Hill, who was not involved in the study.
“The decision to have a mammogram should not be a slam dunk.”


Dr. [Mette] Kalager [an epidemiologist and screening researcher
at the University of Oslo and the Harvard School of Public Health],
whose editorial accompanying the study was titled “Too Much Mammography,”
compared mammography to prostate-specific antigen screening for prostate cancer,
using data from pooled analyses of clinical trials.
It turned out that the two screening tests
were almost identical in their overdiagnosis rate
and had almost the same slight reduction in breast or prostate deaths.

“I was very surprised,” Dr. Kalager, said.
She had assumed that the evidence for mammography must be stronger
since most countries support mammography screening
and most discourage PSA screening.

[Interesting gender difference. What drives it?]

For Women, a More Complicated Choice on Mammograms
by Roni Caryn Rabin
New York Times, 2014-02-12

For women who dutifully keep their mammogram appointments year after year,
the latest results from a long-term trial in Canada,
which found no difference in death rates from breast cancer among
women who had regular mammograms and those who did not,
are bound to sow confusion, perhaps even anger.

For decades now,
the annual mammogram has been promoted vociferously and continuously
as an essential way to protect oneself from breast cancer.
Many women feel they are being irresponsible if they do not get a regular scan,
said Dr. Lisa Schwartz, a professor at
the Dartmouth Institute for Health Policy and Clinical Practice.

“For so long, we have been trying to convince people that
you’re irresponsible or not taking care of yourself
if you don’t do this,” Dr. Schwartz said.
“People were hit over the head with that message.”


In light of the accumulating data that
the benefits of regular mammography may be negligible for women,
and that the practice has led to false positives and overtreatment,
“it’s important for women to realize
there is a genuine decision to be made here,”
Dr. Schwartz said.

It is not a decision that medical groups are making any easier.
In 2009, the United States Preventive Services Task Force,
an influential group that makes recommendations to the federal government,
concluded that
women over age 50 should have mammograms every two years instead of annually
and that the evidence of benefit was only moderate.
The group did not recommend the screening test for younger women.

The report was met with a barrage of criticism.
Some charged that the task force was trying to save health care dollars
at the cost of human lives.


Labels: , , ,