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Detecting and treating prostate cancer: a
surgeon’s perspective
Nicholas C Buchan
PSA testing has become a “hot” topic in recent
years and the debate has only become stronger since the publication of the early
results of the European and American Prostate cancer screening
trials.1–3 Such is the debate and
interest in the topic that it has even overflowed into the popular press with
recent articles published in North and South and Scientific
American.4,5
Unfortunately the debate has left many confused and
uncertain of the role of PSA in prostate cancer management. Much of the debate
has surrounded the role of PSA testing in population based screening in
asymptomatic men. The key tenets of the debate have surrounded whether
or not there is an overall survival benefit and if this survival benefit is
outweighed by the potential for harm from the diagnosis of so called
“insignificant” cancers and the morbidity of treatment.
This very real concern about over treatment is well
recognised and accepted by those treating prostate cancer and there has been a
significant paradigm shift over the last 5 years towards aggressive treatment of
intermediate and high risk disease and away from intervention in low risk
disease. This “uncoupling” of the link between diagnosis and active
treatment will go some way to reducing the harm from over treatment. Another
strategy to reduce this harm is to develop new biomarkers that have accurate
prognostic value in predicting the course of the disease process in individual
patients.
The article published in this issue of the NZMJ by
Lance Ng and colleagues6 titled
Beyond PSA: are new prostate cancer biomarkers of
potential value to New Zealand doctors? is an excellent summary of the
landscape of investigation into prostate cancer biomarkers. Currently there are
no markers that closely rival PSA in clinical practice, but this is a field in
constant evolution.
One of the key difficulties for any prostate cancer
researcher is the long latency period between diagnosis of prostate cancer and
sequelae of the disease. This means that any studies being conducted with
overall survival and cancer specific survival as endpoints need at least 15
years to mature. If a biomarker was developed that was also able to determine
response to treatment this would greatly speed up the development and
investigation of new prostate cancer treatments especially at the early,
potentially curable stages of the disease.
Currently a significant amount of investment has gone into
drug development at the end stages of the disease, partly because it is easier
to measure outcomes later in the disease process as the latency period is
significantly reduced. Whatever opinion you have on prostate cancer population
screening in asymptomatic men everyone agrees that prostate cancer has
a significant impact on the New Zealand population.
Prostate cancer is the third leading cause of male cancer
deaths in New Zealand.7 There is no doubt that
we need to get smarter about the concept of screening in general.
Risk assessment tools may play a central role in the future
when considering whether to biopsy men with an elevated PSA. Such tools enable
both the clinician and patient to quantify the risk of finding prostate cancer
on biopsy and most importantly the specific risk of finding high-grade prostate
cancer.8
A limited number of factors such as age, comorbidity,
prostate volume, family history, ethnicity and previous biopsy status have been
identified to modify risk and are important for consideration in routine
practise.9,10
As the debate surrounding PSA screening has raged what has
been lost in translation is that PSA remains an invaluable test in
symptomatic men as well as in the follow up of men treated for prostate
cancer. As a clinician treating prostate cancer on a daily basis, unfortunately
it is common for me to hear from patients and General Practitioners alike that
they thought that PSA, as a test is “a waste of time”. It is
important that this misconception and extrapolation of the prostate cancer
screening data to symptomatic men be rectified.
It is the right of all male New Zealanders to be well
informed about the benefits and drawbacks of PSA testing and it is our
responsibility as clinicians to enable them to make a risk assessment based on
the most currently available data. Moreover it is the right of all New Zealand
males to have a PSA test if they so choose.
Competing interests: None
declared.
Author information: Nicholas C Buchan,
Urological Surgeon, Christchurch Public Hospital, Urology Associates, and
Canterbury Urology Research Trust Board, Christchurch
Correspondence: Nicholas C Buchan,
Urological Surgeon, Christchurch Public Hospital, PO Box 4345, Christchurch, New
Zealand. Email: nick@urology.co.nz
References:
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