PSA tests: evidence — at last!
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Just 10 days after my post on Crikey expressing concern about the lack of information I received from urologists about the probabilities of various outcomes, following a raised PSA level for testing for prostatic cancer, lo and behold I have said information! It is good news for me, but not such good news for many urologists. The New York Times reported on 19 March on two large studies — “the first based on rigorous randomized trials” — published on the PSA test. In summarising the results the NYT quotes Dr Peter B Bach, a physician and epidemiologist at Memorial Sloan-Kettering Cancer Center:
Hmm … now I know these odds, in future I will not have any PSA tests done — even before I factor in the incontinence and impotence that treatment might bring. But reverting to my more professional role as a health economist, why have all these tests been being carried out and at great financial cost to the taxpayer and the private insurance holder? And what about all the anxiety they have caused? I have never been a big fan of fee for service medicine. Doctors are human and if we pay them according to piecework, of course they will do more pieces. Who wouldn’t? But it is a bit much when they do things that are not evidence based, that can make patients anxious and for which patients struggle to get relevant information on which to make informed choices. Part of the answer is to look very closely at the heavy reliance our health care system has on FFS medicine. If doctors were paid by capitation (ie by the number of people they serve) or by salaries would there be so many PSA tests? Will we see the end of the epidemic of PSA testing? Will we see a decline in the dominance of FFS medicine? Will clinical trials and trials of screening tests in particular please take more account of unnecessary anxiety for patients! |
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10 Comments
From what I have read over the years there has been doubts about PSA tests for a long time; also the rather nasty side effects that can eventuate. Some years ago my local GP asked me if I would like a PSA test, I said no thanks. She didn’t push the matter, in fact I got the distinct impression that she only asked as a matter of form, and that she wasn’t in favor of the test..
So will you have a gastroscopy to investigate your indigestion next?? This is another scandal with enormous cost to the taxpayer, albeit without the impotence/ incontinence side effects.
WENDY NORTHEY
>>Re the PSA test - I am a psychologist. A statistic is just that - a statistic. PSA results should be individually evaluated. What if YOU are that one person in fifty whose life CAN be saved! Randomised tests are all very well. However, to compare eighty-year-old men with fifty-year-old men is irrational. I know personally a number of men in their fifties whose lives have been saved by cancer treatment following a positive psa test. Think again.< <
This is a perfect example of what Prof. Mooney is talking about. In this short paragraph there are so many strange statements:
‘I am a psychologist’: What does this have to do with anything that follows?
‘A statistic is just a statistic’ - No a statistic is a statistic not ‘just’ anything. The papers under discussion have statistics that show that prostate screening is either of no value or results in cancer removal for 48 people for every one person saved.
‘PSA results should be individually evaluated’. Another truism, but we are talking here about screening, i.e. testing, all men over 55 without clinical signs. Where is the ‘individual’ evaluation in that
‘What if YOU are that one person in fifty whose life CAN be saved!’ The point is that we can’t identify that one-in-50, so 48 people have to have unnecessary surgery to save that life. For Prof. Mooney those odds just aren’t good enough.
‘However, to compare eighty-year-old men with fifty-year-old men is irrational’. Both studies looked at men between 50 and 74, so no 80-year olds.
But the clincher is: ‘I know personally a number of men in their fifties whose lives have been saved by cancer treatment following a positive psa test.’ How do you know that - all you know is that they had PSA tests, were found to have cancer and had a prostatectomy. We know from the European study that there are 48 such men for every one man saved, i.e over 96% of the men you know who have had a prostatectomy for cancer did not need it.
Will we see the end of the epidemic of PSA testing? Not while we have patient induced pressure obliging their GPs to provide the test and those gung-ho urologists who continue to zealously promote it. The former find it easier to give in to the patient’s ‘inspired’ demands rather than waste their time in providing balanced information; the latter - the urologists (not all of them) have a vested interest in acquiring another patient. Meanwhile, the pharmaceutical company making the test does pretty well as does the pathology lab. The end results are too many men being treated unnecessarily and a significant proportion ending up with incontinence for an extended period of time and/or impotence. And why is that so many doctors never have a PSA?
know your heredity make your own mind up
Yes Wendy, a male aged 55 to 65 might be the one out of 50 to be saved, but he is considerably be more likely to be one of the 49 out of 50 to be harmed to varying degrees.
Very interesting piece - it highlights how important it is for consumers to be fully informed of the risks and benefits of any tests before they consent to them. Too often in the health system the potential benefits of medical tests are emphasised but not the risks, which leads to an overuse of these tests (who wouldn’t want to have a test that could help detect a cancer early if there was no cost?). And when costs are factored in they tend to be the direct financial cost of the test and not other less obvious costs, such as the anxiety that the test often causes consumers. Pre-natal testing raises similar issues. Many pregnant women are advised to undergo pre-natal screening tests without being informed of all the costs and risks involved, such as the considerable stress and anxiety that some women (although obviously not all) experience in relation to these tests. Balancing the risks and benefits of any medical procedure is vital and this needs to include the consumer’s experience as well as more objective measurements, such as number of disesases detected.
Let’s get this clear - PSA - prostate specific antigen. Not really. The test has value in my opinion when done consistently over time. A one off is money in the pocket of the reagent kit sellers (and there are a few) and not much more. Cancer is not the only reason why a high PSA reading will manifest itself. Infection and Benign Hyperplasia are the other two.
The first PSA I had done was as the result of hectoring by an over zealous GP who had decided that all men over 55 should have various tests done. The result was stress indeed.
I suggest that if we are to use any form of “biomarker” based testing then we make sure that we are looking at a real peptide/protein biomarker for prostate cancer, tested and trialled with tens of thousands of men before go any further. Even then, and assuming we have a no false negative/positive test, are we going to do anything? Maybe we are, but as my urologist said, how the hell do I even FIND a bunch of cancerous cells before they become a lesion big enough for me to remove? Ditto the radiologist.
Re the PSA test - I am a psychologist. A statistic is just that - a statistic. PSA results should be individually evaluated. What if YOU are that one person in fifty whose life CAN be saved! Randomised tests are all very well. However, to compare eighty-year-old men with fifty-year-old men is irrational. I know personally a number of men in their fifties whose lives have been saved by cancer treatment following a positive psa test. Think again.
Derrr..did I miss something or didn’t he say anything?