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PSA testing - a complicated issueYou may have seen news this week that a batch of home test kits that allegedly screen for prostate cancer has been recalled, because they weren’t giving accurate results.

These test kits, like the ones that are available through GPs, are designed to measure the level of a protein called PSA in the blood. They’re meant to indicate whether a man needs further tests for prostate cancer or other prostate conditions. The test kits use a pin-prick of blood, can be bought on the internet and from pharmacies, and are designed to be done at home.

Pros and cons of PSA testing

We’ve blogged before about PSA testing, and the ongoing controversy that surrounds it.  To summarise, there’s not enough evidence that PSA-based screening does more good than harm to men, and so in this country a shared decision-making approach is recommended. After talking to their GPs about the test, and its risks and benefits, men aged over 50 can choose to have the test if they want to. But we don’t have a national screening programme in the UK because scientists can’t be sure that a programme would save lives, and whether it would do more good than harm.

But to get make this shared approach really work, the GP has an important role to play in making sure that men are fully informed about both the benefits and harms, before they decide whether or not to have the test. The doctor is also on hand to give support and interpretation to the results of the test.

The problem with these tests is that PSA is an imperfect marker. By no means all of the men who get a ‘positive’ result in the PSA test will have prostate cancer, as there can be many explanations for men having a high PSA level. And some men who do have prostate cancer don’t have a high PSA level, so they can be missed by this test. This is why it’s important that a doctor can help men to understand the next steps after receiving an abnormal result, and what to expect.

So, given the inherent uncertainties in the PSA test itself, even in the hands of qualified medical professionals, it seems that men would be ill-advised to buy a test that could potentially be even less reliable.

We spoke to our Professor of Cancer Screening, Stephen Duffy, about what he thought about the tests.

“Use of these kits in the UK is unknown but likely to be rare. We don’t encourage them for several reasons. Firstly, despite the recent trial publications, the harm/benefit balance of screening for prostate cancer is still unclear. Secondly, home testing of this nature means that the user may end up with a test result suggesting he may have a serious illness, without the support of a medical professional to help him interpret the result, understand the implications and make confident decisions about what to do next.”

“If men are worried about prostate cancer”, he added, “they should seek professional medical advice rather than buy kits off the internet.”

And on top of all that, there’s no guarantee that the test is as accurate as ones that are done through your doctor, as proven by this recall.

Jean Slocombe, our Senior Cancer Information Nurse, gave her advice too.

“In general, if anyone has symptoms they worry might be cancer we’d recommend they visit their GP rather than buying an off-the-shelf home testing kit. But if any man has purchased a home testing kit since last December and might be worried we recommend he visit his GP.”

All in all, doing a PSA test on your own, at home, isn’t a good idea. Not only do you lose the specialist support of your doctor, who can help you both before and after the test, but the tests could be unreliable.

And there’s no need to pay for the test when it’s available free on the NHS. Men over 50, or who have noticed a change that could be a sign of prostate cancer, can get help and advice from their doctor.

Jess

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