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MAKING
SENSE OF THE PSA TEST FOR PROSTATE CANCER
MALE relatives of prostate cancer patients need more information in
order to help them understand the possible familial risk of the disease,
and to decide whether or not to have a PSA* test, according to research
published in the British Journal of Cancer** today (Tuesday).
The benefit of PSA testing as a screening tool remains uncertain. It may
have value for screening first degree relatives of men with prostate
cancer who are consequently at an increased risk of developing the
disease – about 10 to 15 per cent of British men – but this approach
needs to be fully tested. However, two Cancer Research UK-funded studies
at The Institute of Cancer Research have found that such a targeted
screening programme would be difficult to run and may have a low uptake
by relatives invited to have their PSA levels tested.
There are many unknowns about the PSA test. It can often detect problems
in the prostate at an early stage, but a positive result does not always
mean cancer. As such, getting the result of a PSA test can be a
confusing situation that requires clear information and advice from
health professionals.
The studies were designed to look at how the PSA test could be
practicably used as a possible screening test for relatives of prostate
cancer patients. Results showed that some patients were reluctant to
involve their family members in screening. Many of the relatives who did
respond to the suggestion of screening had already had a PSA test, but
took part because they still felt they needed more information about
prostate cancer.
The PSA test has not been shown to work as a screening test for the
general population, although trials are ongoing. One concern is that a
raised PSA level, while not always indicative of prostate cancer,
nevertheless sometimes leads to invasive investigations that then find
the situation to be normal. There is also doubt over whether screening
using PSA tests would reduce prostate cancer deaths overall.
The NHS currently recommends detailed information that should be
supplied to men who have requested a PSA test so they can make an
informed choice. The authors of The Institute’s studies conclude that
further specific advice may be necessary for prostate cancer patients
with first degree male relatives so they can understand familial risk
factors.
Dr Jane Melia, from The Institute’s Cancer Screening Evaluation Unit,
funded by the Department of Health, said: “We asked prostate cancer
patients if we could invite their brothers and sons to have a PSA test
but found acceptance by those invited to be fairly low. One reason for
this was that many of the invited relatives had already had a test. Some
patients did not agree to the request because they were reluctant to
involve their relatives in screening.
“One reason for the patients’ reluctance was that not all of them
had told members of their family they had cancer. Some men were
concerned about the additional diagnostic tests following a positive
screening result. Encouragingly, among the relatives who did take part,
only a small number experienced high levels of anxiety.”
A prostate cancer screening programme would increase the number of cases
being diagnosed. Not all prostate cancers are aggressive, however, and
other research is underway to find molecular markers that would allow
the accurate assessment of how aggressive a prostate cancer is. Such
markers would enable doctors to reassure some men with a positive test
result, and choose the most appropriate treatment for others.
Dr Melia added: “Our concern is that no one really knows how best to
use this test. Close male relatives of prostate cancer patients form a
relatively small group in the population, so setting up large-scale
randomised controlled trials is not easy. While we wait for the data to
accumulate, prostate cancer patients need information and support to
help them understand familial risk so they and their relatives, if then
told, can make a fully informed decision about the PSA test.”
It has been estimated that inherited genes could account for up to ten
per cent of all cases of prostate cancer. Men with a family history of
prostate cancer in a first degree relative have an increased risk of
developing the disease – two to three times higher than on average.
Dr Lesley Walker, director of cancer information at Cancer Research
UK
, which owns the British Journal of Cancer,
said: “Cancer Research
UK
fully supports cancer screening programmes
where they have been shown to be effective in reducing mortality. In the
case of PSA, the evidence so far suggests it is useful for diagnosing
and monitoring men who already have symptoms associated with prostate
cancer.
“There is an argument for thinking it could also be useful for
screening men at a higher relative risk of the disease, such as close
relatives of prostate cancer patients. This research is an early step
towards evaluating the feasibility of such an approach.”
Notes
* PSA – Prostate Specific Antigen
** Melia et al. “The feasibility and results of a population-based
approach to evaluating prostate-specific antigen screening for prostate
cancer in men with a raised familial risk” British Journal of Cancer
(2006) 94(4) - www.nature.com/bjc/journal/vaop/ncurrent/full/6602959a.html
** Sweetman et al. “Feasibility of familial PSA screening:
psychosocial issues and screening adherence” British Journal of Cancer
(2006) 94(4) - www.nature.com/bjc/journal/vaop/ncurrent/full/6602925a.html
First degree male relatives are father, brother and son only.
More information about cancer screening, prostate cancer, and the PSA
test can be found on the NHS Cancer Screening Programmes website: www.cancerscreening.nhs.uk.
Prostate cancer
Prostate cancer is the most common cancer in British men (excluding
non-melanoma skin cancer), with nearly 32,000 new cases diagnosed each
year.
The greatest risk factor is age – over half of cases are registered in
men over 75.
Monitoring the progress of the disease in older men is often as
effective in terms of survival as radical treatments like radiotherapy
or surgery, and has none of the severe associated side effects such as
impotence and incontinence.
More information about prostate cancer can be found on Cancer Research
UK
’s patient website, CancerHelp
UK
: www.cancerhelp.org.uk.
British Journal of Cancer
The BJC’s mission is to encourage communication of the very best
cancer research from laboratories and clinics in all countries. Broad
coverage, its editorial independence and consistent high standards have
made BJC one of the world's premier general cancer journals.
Cancer Research UK
Cancer Research
UK
's vision is to conquer cancer through
world-class research.
The charity works alone and in partnership with others to carry out
research into the biology and causes of cancer, to develop effective
treatments, improve the quality of life for cancer patients, reduce the
number of people getting cancer and to provide authoritative information
on cancer.
Cancer Research
UK
is the world's leading independent charity
dedicated to research on the causes, treatment and prevention of cancer.
For further information about Cancer Research
UK
's work or to find out how to support the
charity, please call 020 7009 8820 or visit www.cancerresearchuk.org.
The Institute of Cancer Research
The Institute of Cancer Research is
Europe
’s leading cancer research centre with
expert scientists working on cutting edge research. It was founded in
1909 to carry out research into the causes of cancer and to develop new
strategies for its prevention, diagnosis, treatment and care. Website
at: www.icr.ac.uk. The
Institute works in a unique partnership with The Royal Marsden NHS
Foundation Trust, forming the largest comprehensive cancer centre in
Europe
. This relationship enables close daily
contact with those on the frontline in the fight against cancer - the
clinicians, the carers and most importantly, the patients.
(21/2/06)
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