Earlier disease diagnosis leads to more effective treatment and better
outcomes.
Most of us wouldn’t hesitate
in responding true and yet maybe we should.
Early diagnosis can carry risks as well as benefits. During the Bicknell
Lectureship in Public Health at the BU School of Public Health, Dr. H.Gilbert Welch, a professor of medicine, practicing clinician and director of
the Center for Medicine and Media at the Dartmouth Institute for Health Policy
and Clinical Practice, was joined by a panel of health care professionals to discuss
whether we need to reevaluate the value of diagnostic screening.
How early is too early?
Today, Dr. Welch noted, patients are often diagnosed long before
they become symptomatic. Fueled by
improvements in test sensitivity and the availability of new therapies, the diagnostic
threshold for many diseases has been lowered, increasing the number of people
who are classified as needing treatment. The problem with early diagnosis is that there
may be a significant number of these “patients” who may not actually develop health
problems. For this group significant
harm can result from unnecessary treatment.
These patients, according to Dr. Welch, are overdiagnosed.
The popularity paradox
Many of us can probably point to a friend or family member
whose life has been saved by early diagnosis and intervention. However, survivor stories, focusing only on
benefits, can lead to a popularity paradox, making screening appear more
valuable according to Dr. Welch. He
pointed out that it’s also important to look at screening value from a global perspective. Epidemiologists have suggested that even if a
screening test correctly identifies people with preclinical disease, its
effectiveness is measured by its ability to reduce disease related morbidity
and mortality. (1) Yet, according
to data presented by Dr. Welch, the increased incidence of many diseases, such
as thyroid cancer, has been associated with stable death rates. We may be suffering from a diagnosis epidemic not a disease related one.
In October 2011 the US Preventive
Services Task Force (USPSTF) proposed new
recommendations
on PSA screening, advising against its use
in healthy men. Prostate cancer
screening is often cited as a prime example of the problems associated with
overdiagnosis. Writing in the New England
Journal of Medicine, Richard Ablin,
developer of the prostate specific antigen test (PSA), noted that several
studies have found prostate screening did not reduce the death rate in men over
the long term. Ablin urged the medical
community to rethink the use of PSA screening to “rescue millions of men from
unnecessary, debilitating treatments.” Putting this in perspective, Dr. Welch
presented data on prostate cancer that found for every life due to screening, 30 to 100 patients are overdiagnosed.
It’s about better care, not denying care
Dr. Kenneth Lin,
a practicing clinician, Assistant Professor of Clinical Family Medicine at
Georgetown University School of Medicine and former medical officer for the
USPSTF, echoed Dr. Welch. He emphasized
that individual patients and emotional experience cannot be discounted in formulating
screening recommendations; however, this must be countered with evidence
that people can experience harm from overdiagnosis. It’s about striking a balance, he said,
between science and emotion.
Dr.
Deborah Bowen, Chair of the Department of Community Health Sciences at the
Boston University School of Public Health, spoke about genetic screening
tests. She observed that patients may
have difficulty understanding what genetic test results, such “at risk”,
mean. She cited numerous studies which have shown
that patient misunderstanding can lead to anxiety, decreased quality of life,
false assurance and poor choices. In
these cases, she concluded, screening can create more harm than good.
Dr.
John Fallon, Senior Vice President and Chief Physician Executive at Blue
Cross Blue Shield of Massachusetts, explained that employers want to be fair in
determining what screening tests to cover but they also want to see evidence
that screening has value. Furthermore, he emphasized that we need to have the
courage to change course when scientific data suggests clinical practices are
not helpful.
Time to shift priorities?
Dr. Welch and the panelists agreed that more thoughtful
consideration of the risks and benefits of screening is essential to providing
better care for individual patients. As
Dr. Welch noted, it’s important to tell both sides of the story. He added that we may also need to rethink our
health care priorities, focusing more on health promotion versus early
diagnosis. Early diagnosis
focuses on looking more closely for health problems, while health promotion focuses on good preventive
maintenance: eating healthier foods,
exercising regularly, using alcohol in moderation and smoking cessation.
In other words, "is an ounce of health promotion worth a pound of cure?"
You can read more about overdiagnosis in Dr. Welch's book, Overdiagnosed: Making People Sick in the Pursuit of Health. Profits from the book are donated to charity.
You can read more about overdiagnosis in Dr. Welch's book, Overdiagnosed: Making People Sick in the Pursuit of Health. Profits from the book are donated to charity.
(1) Aschengrau, Ann and George R Seage III. Essentials
of Epidemiology in Public Health. Sudbury: Jones and Bartlett, 2008.
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