Gordon Muir

 Erectile Dysfunction

Home 
Practice details 
Research News 
Publications 
Information 
Links 
Referrals 

 

 

 

 

email us

PSA and prostate cancer screening

How dangerous is early prostate cancer?

How effective is radical treatment?

Screening for prostate cancer

Who Should Have a PSA Test?

While men from many countries will be aware of their serum prostate specific antigen (PSA) levels, in the UK there is still limited awareness of prostate cancer in general.

 

This page tries to answer some of the rather complex questions surounding this area.

How dangerous is early prostate cancer?

There is as yet no concrete proof that patients screened for early prostate cancer have an increased life expectancy. However two recent studies from Ausrtia and Canada have suggested survival lbenefits for patients screened for prostate cancer and there appears also to be a genuine reducion in the death rate in the USA (where screening is practised) compared to the UK (where it is not)

Among those studies suggesting an equivalent effect of radical versus expectant treatment there is often a problem with the inclusion of poor performance status men who would not be expected to survive long enough to gain a benefit from radical treatment of what is often a slow growing cancer. Equally, in the many studies showing excellent long term results and cure rates from surgery or radiotherapy, patient selection may make comparison with population studies unreliable.

Nevertheless there is now good evidence from Scandinavia on the fact that for a man with prostate cancer in a given age group, a definable number of years of life will be lost with "watchful waiting": this varies from 14 years for the under fifties to two years for the over seventy five’s.

Regardless of the pronouncement of some critics of treatment, more men are dying of prostate cancer every year. It is also evident that all lethal cancers must at some time have been early, organ confined and potentially curable.

What we are unable to say today is which prostate cancers will progress to kill the patient and which will be safe to observe. As with many cancers, it may be that a number of potentially lethal tumours will not be amenable to a physical curative therapy by the time they are discovered. At present no adjuvant or chemical treatment has been shown to be of benefit unless used with surgery or radiotherapy. There is similarly no agreement as to whether , if radical treatment is beneficial, radiotherapy or surgery is more effective for a given individual patient.

 

How effective is radical treatment?

Many authorities in the UK and Scandinavia have been sceptical of radical treatment for early prostate cancer but in the rest of the world it is the accepted treatment (this does not of course mean it is necessarily right!) Part of the scepticism in the UK might seem to have been unfamiliarity with the surgical techniques involved, since many surgeons who do not support surgery do refer patients for radical radiotherapy.

Recent advances in surgical techniques mean that both treatments can be carried out with a minimal risk of mortality. Both techniques carry a risk of impotence and incontinence: these are probably both slightly higher after surgery although this is operator dependent. Radiotherapy carries a small risk of long-term bowel toxicity which is not seen with surgery. Whereas surgery involves a single operation with several days in hospital followed by a week or so of catheterisation at home, radiotherapy involves a six to seven week course of daily treatments.

A newer form of radiotherapy involves placing radioactive seeds directly into the prostate and may have a lower risk of side effects than the other treatments. We do not however have adequate data for the long term safety of this approach in young men, and not all prostates are suitable for the technique.

My position

I hope to offer curative treatment to patients with clinically organ confined disease who are likely to be at high risk of progression.

In practice this usually means healthy men in their fifties and sixties who have moderate to poorly differentiated tumours, but each patient is treated as an individual. It is important that patients int his position have access to all the resources of aspecialist multidisciplinary team, which we offer at King's and the Lister Hospital.

I believe that surgery is probably more effective than radiotherapy in curing genuinely organ confined disease but that radiotherapy may be superior when the cancer has escaped the confines of the prostate gland.

At present, pre-treatment staging is not perfect, and identification of those patients who will be suitable for treatment forms a part of our research work at King’s College Hospital. An arguable benefit of surgery is that a full pathological examination can be carried out which gives better prognostic information. For younger patients the long term results of surgery may also be superior due to the possibility of second tumours forming in later years if the prostate is left in place.

My hope is that in the next few years we will have some effective adjuvant therapy for minimal residual disease so that the men with locally advanced cancer can be offered a potential cure.

I feel that the firm pronouncement of some specialists on the desirability of non-treatment is nihilistic, biased, and above all unfair to patients who find the concept of prediction of cancer progression difficult and worrying.

Screening for prostate cancer

While there is no official screening programme for prostate cancer in this country it is true that many thousands of men are nonetheless being screened for early prostate cancer.

There are two screening methods that may be used in the screening of prostate cancer: digital rectal examination (DRE) and prostate specific antigen (PSA).

In general those studies which have looked at the place of DRE in screening have found a high sensitivity (for prostatic abnormality) but low specificity (i.e. large numbers of benign diseases picked up). I

PSA is a compound involved in the liquefaction of semen and which is specific to the prostate. In prostate cancer, PSA is liberated to the serum in larger amounts than usual and is elevated in nearly all cases of advanced prostate cancer.

Again however there is a low specificity when looking at the screened population target groups: many of these men will have benign prostatic hypertrophy, which can itself cause small increases in the PSA. The grey zone of PSA between 4ug/l to 10 ug/l is of great difficulty for the urologist. Of these men around 25 to 30 % will have prostate cancer, but to prove this means carrying out biopsies in 70-75% of men who will have benign swelling or inflammation of the prostate.

Various PSA isoforms have been proposed as helping improve the specificity (e.g. the free / total PSA ratio); currently they all seem to share the problem of lowering the sensitivity of the test to a level that means missing unacceptable numbers of cancers unless patients are closely followed up.

At King's College Hospital one of our areas of research interest is using new forms of PSA to improve the accuracy of these tests. Further research in the next year may clarify the place of these more advanced assays.

More and more men are asking for PSA testing now and informed consent is most important since there may be significant implications of an abnormal test.

  Recommendations for patients in whom serum PSA testing is justified:

The American Urological Assocation recommends annual rectal examination and PSA testing for all men over the age of 45 years, and from 40 years in men at higher risk of prostate cancer.

The Department of Health in the UK has stated that it does not believe any men should be screened for prostate cancer!

Clearly there is some discrepancy here…..

While the ideal would be to have a prospective controlled trial of the effect of screeining, it must be accepted that this may never take place.

My recommendations for PSA testing are:

  • Fit men of any age with symptoms of bladder outflow obstruction
  • -the presence or absence of a tumour may influence treatment decisions

  • Fit men with a life expectancy of ten years or more who are interested in prostate cancer screening
  • -a small cancer would indicate discussion of radical treatment

  • Fit men over 40 years old with a family history of prostate cancer or breast cancer, or in men aith a high racial incidence (eg Black men)
  • -a small cancer would indicate discussion of radical treatment 

  • Men with an abnormal digital rectal examination of the prostate
  • -Very high PSA accurately diagnoses metastatic prostate cancer :such patients should at least be observed and usually treated by hormones

  • Men over 40 with haematuria (blood in the urine) or haematospermia (blood in the semen)
  • the presence or absence of a tumour may influence treatment decisions

     While these policies will tend to exclude elderly men from PSA testing, I would stress that this is not an "ageist" approach but rather one which recognises the uncertainty of treatment outcomes for screen detected prostate cancer, particularly in men with an actuarially predicted survival of less than ten years.

It should be realised that any man having a PSA test should be aware that the test may lead to recommendation of further tests or procedures which may have side effects and which may cause anxiety. In men at high risk (race, family history) it is probably sensible to have an initial assessment at 40 years and then formulate an individual follow up plan thereafter.

If there are any queries on individual patients then an informal approach for advice will always be welcome.

 

 

PSA is also known jokingly as"Promotor of Stress and Anxiety"

You should not let it worry you to this degree!

[Practice details][Research News][Publications][Information][Links][Referrals]

Copyright (c) 1999-2001 GH Muir. All rights reserved.
mail@london-urology.co.uk