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But caution warranted for the PSA test

A version of this commentary appeared in the Red Deer Express

These days, you can find traces of Movember everywhere.  I’ve even seen traces on myself.  When I look in the mirror every morning I see the salt and pepper stubble of a guy who stopped shaving his upper lip two weeks ago at the urging of a friend who lost his dad to prostate cancer.

I’m not unlike many Canadian men boasting moustaches, goatees and beards and I have no problem with supporting better research into this disease even as I know there are problems with a central part of the Movember message: that you need to find cancer early before it gets you.

As more research comes in, it is increasingly clear that the evidence isn’t keeping up with the hype.

If cancer screening was living up to its billing, we should be detecting cancer earlier and saving lives that would otherwise be lost. Though this might be the case with colon and cervical cancer screening, it isn’t necessarily true with one of the most controversial screening programs around: prostate-specific antigen (PSA) testing for prostate cancer.

The positives and negatives of PSA testing
Prostate screening typically involves both a digital rectal exam and a blood test that measures the amount of circulating PSA, a protein produced by the prostate. If a man has a high PSA count, it could mean a lot of things, such as inflammation or an infection of the prostate. Or it could mean cancer.

Let’s be clear: PSA testing can detect prostate cancer early. And treatment for prostate cancer may be more effective when it’s found sooner, rather than later.

Still, there is a lot of evidence that hints that PSA testing is not a total slam dunk.

For instance, prostate cancer screening can result in false positives leading to subsequent tests, more anxiety, and in most cases, unnecessary treatment. And there are serious potential side effects associated with prostate cancer therapy — such as impotence or incontinence.

Besides the potential for false positives, perhaps the most worrisome thing about PSA testing is that it creates a huge demand for biopsy tests, which use needles to pierce the prostate and are capable of making perfectly healthy men sick. This procedure carries an infection risk because the needle can sometimes transfer bacteria from the bowel into the prostate, bladder, and bloodstream. A recent story in Bloomberg News reported that as many as five per cent of men undergoing a prostate biopsy may experience serious, life-threatening infections.

Crunching the numbers
Also, it is still unclear whether prostate cancer screening saves lives in the long run.

A recent American study, which monitored a group of men aged 55 and older over 10 years, found that there were no additional lives saved by carrying out PSA screening. Meanwhile, a European study showed that to save one life, 1,410 men would need to be screened and 48 men would need to be treated. The question remains — how many unintended problems were produced in the other 1,409 men who were screened — 47 of which were also treated?

The fact of the matter is that most men over 60 have prostate cancer, according to a decision guide published by the US Centre for Disease Control.

Though this might seem like an alarming statistic, many cancers are so slow growing they would never spread and kill. Though 60 per cent of men in their 60s have some form of prostate cancer, only 3 men in a 100 are going to die from it. Most men, who live long enough, die with prostate cancer, but not because of having it. Yet if you’ve gone through the PSA mill, and cancer has been detected in your prostate, it’s difficult to say: let’s wait and see what happens.

Despite all the controversies around PSA testing, there is one solid and indisputable common ground: men need to go into prostate screening with their eyes wide open — and they need to agree to it only after a full assessment of the possible good, the bad and the ugly of PSA testing. Perhaps the best place to start is reading a reasonably good and informative factsheet, and preparing yourself for the inevitable discussion with your doctor.

Has modern medicine overpromised when it comes to saving men from prostate cancer deaths? Undoubtedly, it has.

I’m growing a ‘stache thinking of my friend’s dad, and hoping that we can balance out those promises with another: let no man submit to a PSA test until he is clear on what his real risks are — both from having the test and from not having it.

Alan Cassels is a drug policy researcher at the University of Victoria and the author of Selling Sickness. He is also an expert advisor with EvidenceNetwork.ca.

November 2011

This work is licensed under a Creative Commons Attribution 4.0 International License.