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Latest Prostate
Research Developments
By
Joe Parisi
January 14,
2008
Comments: My very first article
Researchers Say They Have Found a Better Test for Prostate Cancer?
Well, here we go
again. A new yearly test to determine if us guys have prostate cancer!
Prostate cancer is
one thing that us seniors worry about all the time. More than 200,000 of
us are expected to be diagnosed with it this year and it is expected to
kill 27,000 men. The seriousness of this threat, combined with the
success in its treatment puts a high premium on early detection, which
now relies on a less-than-perfect system. That is why a new, promising
screening method grabbed the headlines recently. Read More
“Better Blood Test for Prostate
Cancer,” is the headline on the news release from John Hopkins
University School of Medicine.
It says new studies of a blood protein recently identified at Johns
Hopkins, early prostate cancer antigen-2 (EPCA-2), may change the way
men are screened for prostate.
Current standards of screening and testing for prostate cancer focus on
the blood protein prostate-specific antigen (PSA) along with a digital
rectal examination.
PSA testing, however, often erroneously highlights noncancerous
conditions (false positives) and can miss some cases of cancer (false
negatives), according to Robert H. Getzenberg, Ph.D., professor of
urology and director of research at the James Buchanan Brady Urological
Institute at Johns Hopkins.
Due to elevated PSA levels, approximately 1.6 million men undergo
prostatic biopsies in the United States annually, and roughly 80 percent
of these men have negative results, according to Getzenberg, lead author
of the study.
He says that of the entire population of men in the United States who
have been tested for PSA, an estimated 25 million have elevated PSA
levels and a biopsy of the prostate that did not reveal any prostate
cancer. Conversely, roughly 15 percent of men with prostate cancer go
undetected because their PSA levels are below the cutoff level,
according to Getzenberg.
In a study published in the April issue of the journal Urology,
Getzenberg and a team of Hopkins researchers introduce evidence in
support of EPCA-2 testing as a more accurate way to identify cancer in
the prostate.
“A blood test based on EPCA-2 may greatly improve our ability to
accurately detect prostate cancer early and minimize the number of false
positives, therefore lowering the number of unnecessary biopsies,” says
Getzenberg. “In addition, this is the first time we have a test that
effectively distinguishes between men with cancer confined to the
prostate and those whose disease has spread outside of the gland.”
Getzenberg and his team measured EPCA-2 levels in the blood of 330
Hopkins patients separated into several groups: men with normal PSA
levels and no evidence of disease; men with elevated PSA levels but who
had negative biopsies, men with a common noncancerous prostate condition
known as benign prostatic hypertrophy (BPH) who did not receive biopsies
for prostate cancer, men with prostate cancer but with normal PSA
levels, men with prostate cancer confined to the prostate, men with
prostate cancer that had invaded outside of the gland at the time of
surgery, and a diverse group of patients with benign conditions of other
organs as well as individuals with other cancer types.
Patients with an EPCA-2 cutoff level of 30 nanograms per milliliters or
higher were considered to be at risk for prostate cancer. This cutoff
was based on a pilot study of 30 blood samples, which was then applied
throughout the larger study.
Results showed that the EPCA-2 test was negative in 97 percent of the
patients who did not have prostate cancer. Men with no evidence of
disease (regardless of their PSA levels), as well as the control group
of patients with other cancer types and benign conditions, all had
EPCA-2 levels below the cutoff.
In contrast, in a multi-institutional study published in 2003 in the
Journal of Urology, PSA levels between 4 and 10 nanograms per milliliter
were shown to be accurate in identifying patients without prostate
cancer only 19 percent of the time.
In addition, 77 percent of the BPH patients had a level of EPCA-2 lower
than the cutoff point. Getzenberg says this is well within the likely
percentage range of BPH patients who are prostate-cancer free. He says
this result was encouraging since BPH is often associated with elevated
PSA levels, leading to misdiagnosis and unnecessary biopsies.
When it came to correctly identifying patients with prostate cancer,
EPCA-2 levels at or above the cutoff were detected in 90 percent of the
men with organ-confined prostate cancer and in 98 percent of the men
with disease outside the prostate. Overall, in this study, the EPCA-2
test detected 94 percent of the men with prostate cancer.
Results of the study also revealed that EPCA-2 levels were significantly
higher in patients whose cancers had spread outside the prostate
compared to those with disease confided to the gland. EPCA-2 was
dramatically better at separating these groups than were PSA levels,
according to Getzenberg.
“This is important, since cancer that has spread outside the prostate is
more deadly, which makes it even more crucial to have a tool that
detects it early,” says Getzenberg.
An optimized version of the assay, evaluated in a separate set of 55
patients, supported the earlier findings. Finally, the EPCA-2 test
identified 78 percent of the men with prostate cancer in the group with
PSA levels below the accepted cutoff level of 2.5 nanograms per
milliliter. According to their PSA levels, these were all “healthy men,”
but EPCA-2 was able to show that they had prostate cancer.
Will EPCA become a reliable yearly standard test for all of us? I sure
hope so! |
