cancer cell .
(photo credit: Thinkstock/Imagebank)
BOSTON – Physicians advising men whether to be screened for prostate
cancer with a PSA test must rely more on available evidence when recommending
screening, biopsies and treatments rather than long held beliefs that PSA-based
testing is beneficial for all, Beth Israel Deaconess Medical Center prostate
expert Marc B. Garnick, MD, says.
Writing in the February edition of
Scientific American, Garnick states the current system that relies on
prostate-specific antigens levels in the blood is “deeply flawed,” and
physicians must take into account the fact “the PSA test does not tell you if a
man has cancer, just that he might have it.”
The recent US Preventative
Services Task Force’s assessment of studies published in 2009 shows more harm
than good results from PSA testing, and that evidence favors moving away from
aggressive early treatment for all and toward a more cautious, individualized
approach – an approach currently underway at BIDMC.
“Most people outside
the medical community do not realize how flimsy evidence has been in favor of
the PSA screening data,” says Garnick, who is also an editor-in-chief of Harvard
Medical School’s Annual Report on Prostate Diseases and associated
“In a perfect world, a screening test would identify only
cancers that would prove lethal if untreated. Then, men who had small, curable
cancers would be treated, and their lives would be saved. Ideally, the
treatments would not only be effective, they would have no serious side effects.
Such a scenario would justify massive screening and treatment of everyone with a
However, doctors currently do not have a reliable way to
determine which of these small cancers, caught by biopsy, are potentially
dangerous and which would not cause harm throughout a man’s lifetime. Moreover,
all of the current treatments carry significant risks and long term side
Despite successfully preventing a single death from prostate
cancer, the number of men who would have to be treated and potentially suffer
the consequences of treatment to achieve this prompted the Task Force to
recommend against wide spread PSA testing for all men without symptoms of
prostate cancer. according to Garnick.
In two studies from 2009, one
conducted in Europe and the other in the US, healthy men in their 50s and 60s
were randomly divided into two groups; one was periodically screened for
prostate cancer using PSA testing or a digital rectal exam, or both. The other
group was not offered routine testing, but received standard medical care as
The European study showed that only the men who were tested and
treated for prostate cancer had a 20 percent likelihood of dying from the
disease, while neither study showed if the men who were tested and treated lived
any longer than those who were not offered routine testing. Such a decrease in
prostate cancer mortality was not found in the U.S. study.
European study, researchers then determined that in order to save one life from
prostate cancer, approximately 1,400 men would have to undergo screening, which
would result in 48 having to undergo treatment. The remaining 47 could suffer
serious side effects, such as incontinence and impotence, as a result of
radiation or surgery.
“The overall death rate from all causes was not
statistically different in both the screened and un-screened groups,” says
Garnick. “Unfortunately, the mortality data collected over the past 25 years
shows that the natural history of prostate cancer is not as straightforward as
my colleagues and I once believed. Many cancers will never cause problems during
the patient’s lifetime, and hence do not need to be treated, at least
Results from a long-term Canadian study indicate that the
death rate from the disease for men who elect active surveillance, or choosing
to delay treatment after a PSA test led to the diagnosis of cancer is 1 percent
over 10 years, compared with a 0.5 percent risk of dying from complications in
the first month after prostate cancer surgery.
“The point is that the
initial decision to forgo treatment is not necessarily the final one. Surgery,
radiation and other therapies are still available later on, and most current
data indicate that the outcome will not be negatively affected by the delay.
Such an approach is improving our ability to tailor treatments for individuals
rather than always treating everyone the same,” says Garnick.
outcomes of this decision indicate that doctors and patients need to be clear
about their knowledge, and lack of knowledge, from a scientific point of view
especially as we discuss these issues with our patients. “We need to have the
courage to act on the evidence and not just our beliefs,” says
Garnick.Beth Israel Deaconess Medical Center is a patient care, teaching
and research affiliate of Harvard Medical School, and currently ranks third in
National Institutes of Health funding among independent hospitals nationwide.
BIDMC is clinically affiliated with the Joslin Diabetes Center and is a research
partner of Dana-Farber/Harvard Cancer Center. BIDMC is the official hospital of
the Boston Red Sox. For more information, visit www.bidmc.org.This article was first published at www.newswise.com