Elderly Men with Short Life Expectancy Do Not Need
Prostate Cancer Screening, Study Shows
U.S. trial shows no early mortality benefit from
current annual screening for prostate cancer - watch video, link below
See link to video
below in news report
March 19, 2009 - The prostate cancer screening
tests that have become an annual ritual for many older men don't appear
to reduce deaths from the disease among those with a limited
life-expectancy, according to early results of a major U.S. study
involving 75,000 men.
Results released yesterday from the Prostate, Lung,
Colorectal and Ovarian (PLCO) Cancer Screening Trial show that six years
of aggressive, annual screening for prostate cancer led to more
diagnoses of prostate tumors but not to fewer deaths from the disease.
The study, led by researchers at Washington
University School of Medicine in St. Louis and conducted at 10 sites,
appeared online March 18 in the New England Journal of Medicine
(and in the journal's print edition on March 26).
"The important message is that for men with a life
expectancy of seven to 10 years or less, it is probably not necessary to
be screened for prostate cancer," says the study's lead author and
principal investigator Gerald Andriole, M.D., chief urologic surgeon at
the Siteman Cancer Center at Washington University School of Medicine
and Barnes-Jewish Hospital.
But it's too soon, he added, to make broad
screening recommendations for all men based on the study's initial
findings.
"So far, only a minority of men enrolled in the
PLCO study have died, so it may be premature to make generalizations
about the ultimate results of the trial," he says.
"We don't have enough
data yet about the youngest men in the study - those in their 50s - and
it may be that over time, we will, in fact, see a benefit from
screening."
Nearly 6,400 men are enrolled in the study at
Washington University. Robert Grubb III, M.D., assistant professor of
surgery, is a collaborator and the study's second author.
The PLCO trial began in 1992 with funding from the
National Cancer Institute and was designed to determine whether prostate
cancer screening reduces deaths from the disease.
Sarcosine is better indicator of advancing disease
than traditional prostate specific antigen test (PSA); it is detected in
urine, researchers hopeful simple urine test can be used
It involves men ages
55 to 74 who received either annual PSA blood tests and digital rectal
exams or "routine care," meaning they had the screening tests only if
their physicians recommended them.
After seven to 10 years of follow up,
deaths from prostate cancer were very low in both groups and did not
differ significantly between the groups.
Prostate Cancer
The prostate is the gland below a man's
bladder that produces fluid for semen. Prostate cancer is the
third most common cause of death from cancer in men of all ages.
It is rare in men younger than 40.
Levels of a substance called prostate
specific antigen (PSA) is often high in men with prostate
cancer. However, PSA can also be high with other
prostate conditions. Since the PSA test became common, most
prostate cancers are found before they cause symptoms. Symptoms
of prostate cancer may include
>> Problems passing urine, such as pain,
difficulty starting or stopping the stream, or dribbling
>> Low back pain
>> Pain with ejaculation
Prostate cancer treatment often depends
on the stage of the cancer. How fast the cancer grows and how
different it is from surrounding tissue helps determine the
stage. Treatment may include surgery, radiation therapy,
chemotherapy or control of hormones that affect the cancer.
Health guidelines issued last year by the U.S.
Preventive Services Task Force recommend against prostate cancer
screening for men age 75 or older and concluded there is insufficient
evidence to assess the balance of benefits and harms of prostate cancer
screening in men younger than 75. However, the American Urological
Association and the American Cancer Society recommend annual prostate
cancer screening tests beginning at age 50 for most men.
More than 186,000 U.S. men will be diagnosed with
prostate cancer this year, and nearly 29,000 will die from the disease,
according to the National Cancer Institute. PSA blood tests, introduced
in 1988, have increasingly been used as a screening tool for prostate
cancer, despite a lack of evidence showing they reduce death rates from
disease.
The controversy over prostate cancer screening has
arisen because most men who undergo a biopsy for an abnormal PSA test do
not have prostate cancer. For those who have cancer, the tumors
generally grow so slowly that most men die of other causes. Furthermore,
prostate cancer treatment can result in incontinence and impotence.
However, some tumors can be aggressive, and the difficulty has been
distinguishing aggressive cancers from those that are slow growing.
"We definitely need to find better ways to detect
and treat aggressive tumors, those that are truly life-threatening, so
that men with slow-growing tumors can avoid unnecessary treatments,"
says Andriole.
Today's results are the first to detail death rates
from prostate cancer among men in the PLCO study and are being released
to coincide with the presentation of the data at the European
Association of Urology meeting in Stockholm, Sweden.
The PLCO data are being made public now because the
study's Data and Safety Monitoring Board, an independent review
committee that meets every six months, saw a continuing lack of evidence
that screening reduces deaths due to prostate cancer as well as the
suggestion that screening may cause men to be treated unnecessarily. The
PLCO investigators will continue to follow patients for several more
years to see whether annual screening eventually reduces prostate cancer
deaths.
The trial involved 76,693 men, who were randomly
assigned to receive either annual PSA blood tests for six years and
digital rectal exams for four years or routine care, which included
physical checkups but no mandate for annual prostate cancer screening.
The new report includes data for all participants
seven years after they joined the trial and for 67 percent of
participants 10 years after they joined the trial.
At seven years, there were 22 percent more prostate
cancer diagnoses in the men screened annually (2,820 men in the
screening group vs. 2,322 in the routine-care group). This trend has
continued in data collected up to 10 years (currently there are 17
percent more prostate cancer diagnoses in the screening group).
Deaths from prostate cancer did not differ
significantly between the groups. Seven years after the start of
screening, there were 50 deaths from prostate cancer in the screening
group and 44 deaths in the routine-care group. Ten years after the start
of screening, there were 92 prostate cancer deaths in the screening
group and 82 in the routine-care group.
"My recommendation is that, for now, men with a
life expectancy of more than seven to 10 years continue to be screened
for prostate cancer," says Andriole. "On the other hand, screening is
probably not necessary for elderly men and men with significant health
issues. These men should have a conversation with their doctors to make
an individual decision about whether they want to be screened, because
clearly there can be harmful side effects related to treatment, while
for these men, there has been no demonstration that screening will
prolong their lives."
Of the men who received annual screening, 85
percent had PSA tests and 86 percent had digital rectal exams. Men in
the routine-care arm sometimes had prostate cancer screening tests: PSA
screening ranged from 40 percent of men at the beginning of the study to
52 percent of men by the last screening year, and screening with rectal
exams ranged from 41 percent initially to 46 percent by the last
screening year. The exam involves a doctor inserting a lubricated,
gloved finger into the rectum to feel for anything that is not normal.
Men were referred for follow up testing for
prostate cancer if their PSA level was higher than 4.0 ng/ml or if the
rectal exam was abnormal.
The researchers noted that the vast majority of men
in both groups who developed prostate cancer were diagnosed with stage
II disease (out of IV). The number of later-stage cases was similar in
the two groups. However, men in the routine-care group had more
aggressive tumors (Gleason score 8-10). The reduced number of men with
prostate cancer with a Gleason score of 8-10 in the intervention group
may eventually lead to a mortality difference, but data analyzed so far
have not shown such a benefit.
Additionally, men in both groups received similar
treatments for their disease, which was not dictated by being a
participant in the PLCO.
Another study reported in this same online issue of
the NEJM is the large European Randomized Trial of Screening for
Prostate Cancer (ERSPC), which shows a 20 percent reduction in the rate
of death from prostate cancer but with a high risk of overdiagnosis. In
the ERSPC, unlike the PLCO trial, men were referred for follow-up
testing if their PSA level was 3.0 ng/mL or higher and were also
screened, on average, every four years as opposed to annually in the
PLCO.
Lowering the threshold for what is considered an
abnormal PSA to 3.0 ng/ml is likely to diagnose more tumors but not
necessarily identify those that are more likely to be aggressive,
Andriole says.
Information source:
Original story by Caroline Arbanas, WUSTL News &
Information
Andriole GL, Grubb RL, Buys SS, Chia D, Church TR,
Fouad MN, Gelmann EP, Kvale PA, Reding DJ, Weissfeld JL, Yokochi LA,
Crawford ED, O'Brien B, Clapp JD, Rathmell JM, Riley TL, Hayes RB,
Kramer BS, Izmirlian G, Miller AB, Pinsky PF, Prorok PC, Gohagan JK, and
Berg CD. Mortality Results from a Prostate-Cancer Randomized Screening
Trial. Online March 18, 2009. In print, March 26, 2009. Vol. 360, No.
13. New England Journal of Medicine.
Washington University School of Medicine's 2,100
employed and volunteer faculty physicians also are the medical staff of
Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine
is one of the leading medical research, teaching and patient care
institutions in the nation, currently ranked third in the nation by U.S.
News & World Report. Through its affiliations with Barnes-Jewish and St.
Louis Children's hospitals, the School of Medicine is linked to BJC
HealthCare.
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