|
E-mail this page to a friend!
Senior Citizen Health & Medicine
Researchers Say They Have Found a Better Test for
Prostate Cancer?
Search for something better than PSA leads to
EPCA-2
April 26, 2007 Prostate cancer is one thing that
almost every male senior citizen worries about at some time. More than
200,000 men are expected to be diagnosed with it this year and it is
expected to kill 27,000. 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 today.
| |
Related Stories |
|
| |
Proteins from Inflammation are 'Smoking Gun' in
Spread of Prostate Cancer
Prostate biopsies, may, ironically, hasten
progression of metastasis
March 19, 2007
Obesity and Prostate Cancer a Deadly Combination,
Study Finds
More than two-and-a-half times the risk of dying
compared to men of normal weight
March 15, 2007
Seniors May Increase Risk of Heart Disease from
Prostate Cancer Treatment
Longer they received ADT, the sooner they were likely
to die
Feb. 26, 2007
Prostate Cancer
Patients Have High Survival Rates with Seed Implants
'Quality of the seed implant is a critical ingredient for
achieving a better outcome'
January 31, 2007
Radiation Therapy Combo Cures Prostate Cancer
Long-Term
Author says it's 'good news' since radiation
therapy is less invasive, spares healthy tissue, faster recovery than
surgery
January 4, 2007
Lack of Sons Puts Men at Higher Risk for Prostate
Cancer Says New Study
The more sons a man has the lower his prostate
cancer risk
January 3, 2007
Elderly Men Survive Prostate Cancer 'Significantly'
Longer if Treated
Editorial says best care achieved not by treating
more patients but by treating them more discerningly
December 22, 2006
Octogenarians Not Too Old for Cancer Surgery, Say
Mayo Clinic Researchers
Increased wellness, safer anesthesia make it
possible for older adults to safely and effectively have surgeries, in
this case radical prostatectomy
November 27, 2006
Prostate Cancer Studies Find Benefit to Radiation,
No Harm in Testosterone Replacement in Older Men
November 14, 2006
Prostate Cancer Cells Killed by Protein Made by the
Cancer
Senior citizens with cancer or enlarged prostate
may be helped by discovery
November 10, 2006
Researchers Urge New Approach to Prostate Cancer
Screening with Early PSA Base
Even a slight change
in PSA may indicate a potential for cancer
November 1, 2006
Prostate Cancer Appears Cured in 89 Percent of Men
Treated with IMRT
After eight years
they are alive and show no signs of cancer
September 27, 2006
PSA of Prostate Cancer Victims Can Predict How Long
They Will Survive
Patients with lower PSA levels 7 months after
therapy lived longer
By Nicole Fawcett, University of Michigan Health System
August 25, 2006
Read the latest news on Senior
Health & Medicine |
|
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.
| |
Is PSA Screening a Waste on Older
Men?"
A study of almost 600,000 men aged 70 and older,
released last November, revealed that 56 percent had a routine
prostate-specific antigen (PSA) screening, a blood test for prostate
cancer, even though no treatment guidelines recommend PSA screening for
men of that age.
Screening rates declined with age, but overall
health had little or no impact on whether a PSA test was performed.
In fact, says lead author Louise C. Walter, MD, a
staff physician at the San Francisco VA Medical Center, health status
had so little bearing on the decision to screen that 36 percent of men
age 85 and older who were in poor health and at high risk of dying
within a year were given the test.
"Not a single professional organization,
physicians' group, or prostate cancer advocacy group advocates PSA
screening for frail, elderly men, and yet we are doing it," says Walter,
who is also an assistant professor of medicine at the University of
California, San Francisco.
The study appeared in the November 15, 2006 issue of
the Journal of the American Medical Association.
In general, performing the PSA test on men 70 and
older is a poor idea for a number of reasons, says lead author Louise C.
Walter, MD, a staff physician at the San Francisco VA Medical Center.
"First, as you grow older, there's good evidence
that PSA becomes less accurate. Second, not all prostate cancers are
alike."
The PSA test is best at detecting slow-growing
cancers that will have a health impact 10 to 15 years after they are
found, Walter explains, while it tends to miss aggressive, fast-growing
cancers. "Third, it's been well-documented that older men, particularly
those with chronic or severe illnesses, have more complications from all
types of prostate cancer treatment than younger men." Finally, says
Walter, even if no treatment is performed, simply the knowledge of an
elevated PSA causes anxiety and thus has a negative impact on quality of
life.
"This is why no guideline recommends PSA screening
for men who, taking health status as well as age into account, have a
life expectancy of 10 years or less," concludes Walter.
|
|
EPCA-2 is the second prostate-cancer marker
identified by Getzenberg and his team that has outperformed PSA. Last
year, they discovered an unrelated, tissue-based test, EPCA-1, that also
proved effective at identifying prostate cancer. The only commonality
between these markers is that they were discovered using the same
approach. Getzenberg says the efficacy of EPCA-1 as a test of biopsy
samples is currently being evaluated.
"While experts say the new test is promising, they say it's too
soon to know whether it really works better than older screening
methods," write Liz Szabo in USA TODAY.
Ian Thompson, chairman of urology at the University
of Texas Health Science Center in San Antonio told Szabo he doubts the new
test will replace the PSA. Instead, doctors likely will incorporate new
biomarkers into a panel of tests that will help men gauge their risk of
prostate cancer, says Thompson, who was not involved in the study.
Howard Parnes of the National Cancer Institute, who
also was not involved in the Johns Hopkins study, pointed out to Szabo that prostate
screenings have not yet been shown to save lives. Finding more cancers
could actually lead to "overdiagnosis" and "overtreatment," in which men
are treated for slow-growing tumors that don't really need to be found.
An ideal screening test, he says, would call attention only to lethal
cancers.
Prostate cancer is the most common type of cancer
found in American men. The American Cancer Society estimates that there
will be approximately 218,890 new cases of prostate cancer in the United
States in 2007, and 27,050 men will die of this disease.
Getzenberg says larger clinical trials for EPCA-2
are planned that could make this test available to the public in
approximately 18 months.
Funding for the study was provided by the National
Cancer Institute of the National Institutes of Health, and Onconome Inc.
Under a licensing agreement between Onconome Inc.
and the University of Pittsburgh, Getzenberg is entitled to a share of
royalty received by the University on sales of products described in
this manuscript. Getzenberg also is a paid consultant to Onconome Inc.,
which has a licensing agreement with The Johns Hopkins University
covering EPCA-2 and related technologies. The terms of this arrangement
are being managed by The Johns Hopkins University in accordance with its
conflict of interest policies.
Other researchers from the Brady Urology Institute
at Johns Hopkins who contributed to this study are Eddy S. Leman, Ph.D.;
Department of Urology Chairman Alan W. Partin, M.D., Ph.D.; Daniel W.
Chan, Ph.D.; Bruce J. Trock, Ph.D.; Lori J. Sokoll, Ph.D.; Leslie
Mangold, and Grant W. Cannon.
>>
Read full story in USA Today
>>
Watch Video on New EPCA-2 Prostate Screening
Click to More Senior News on the
Front Page
Copyright: SeniorJournal.com |
