seldom tell patients about the possible harms of getting screened for cancer, a
new study shows. During any screening test, there is a chance of so-called overdiagnosis – finding something that looks like cancer but isn't, or a cancer
that's so small and slow-growing it would never cause a problem.
In those cases, patients may get biopsies,
surgeries, radiation and drugs that won't bring them any benefit, but could
come with side effects, known as overtreatment. "Usually when you talk to
your doctor, you only learn about the benefits," said Odette Wegwarth.
She led the
study at the Max Planck Institute for Human Development in Berlin. "Nobody
questions whether there could potentially be any harm," Wegwarth said.
of overdiagnosis and overtreatment varies from one screening test to another
and isn't always known. With PSA tests to detect prostate cancer and mammograms
for breast cancer, there are 10 or more cases of overdiagnosis for each life
saved, the researchers write.
Risks of screening
and her co-author Gerd Gigerenzer surveyed 317 American adults in their 50s and
60s. All of those people had been invited to undergo cancer screening by their
doctors in the past. None had been diagnosed with cancer. Just 30 of the
participants – less than one in 10 – said their doctor had brought up the
chance of overdiagnosis and overtreatment when talking about screening.
But 80% said
they would want to be told about those potential harms. It's possible some
people in the study were told about overdiagnosis, but they don't remember it
or doctors talked over their heads, said David Howard, a health policy
researcher at Emory University in Atlanta, who was not involved in the new
But he also
said many doctors probably aren't bringing up the risks of screening. "Many
doctors themselves may be vaguely aware of the concept of overdiagnosis, but
unaware of the magnitude or unable to quantify the risk," he told Reuters
Health. "I can also imagine physicians being wary of introducing the topic because
it also prolongs the visit... and out of concern that patients might not be
able to understand it.
people in the study said they would continue with cancer checks they were
already receiving regularly if they learned 10 people would be overtreated for
each life saved by the test. But 69% would not start a new screening test that
had those odds, according to the findings published in JAMA Internal Medicine.
said people seem to have "an emotional attachment" to screening tests
they get regularly. "It's probably really difficult to make people
understand that the screening they believe in can be sometimes bad too,"
she told Reuters Health.
believe in what they have been taught and told." But just about everything
in medicine comes with a downside, Wegwarth said.
patients, Howard recommended "going into the conversation with the
physician being ready to ask questions." Dr H. Gilbert Welch from The
Dartmouth Institute for Health Policy and Clinical Practice in Lebanon, New
Hampshire, advised seeking out information about overdiagnosis even before
going to the doctor.
is not a simple discussion," Welch, who wrote a commentary published with
the study, told Reuters Health. "The truth is these are complex enough
issues that the patients need some time with these ideas before they come to
the doctor's office."