New prostate cancer test which studies the tumour to help determine how aggressive it is could save men's sex life

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John Murphy opted to pay privately for a new test (picture posed by model)

John Murphy was devastated to be diagnosed with prostate cancer last November. A routine blood test showed the 56-year-old builder had raised PSA (prostate specific antigen) levels, which can indicate a problem with the prostate.

An MRI (magnetic resonance imaging) scan and biopsy showed he had several tumours around his prostate, the walnut-shaped gland that surrounds the urethra, the tube which carries urine from the body.

'My first reaction was to have my prostate removed surgically as soon as possible, which my urologist said was the safest option because the prostate and cancer would be gone,' says John, who lives near Slough in Berkshire and is married with three children.

John was warned that surgery carried risks of incontinence and impotence, because it could damage nearby nerves that control sexual and bladder function.

Initially he was happy to take his chances, but three days before the operation, he changed his mind. 'I wanted more time to think,' he says. 'My wife Sue and I are very close, and I'm relatively young.'

Instead, John opted to pay privately for a new test that studies the genes in a tumour to help determine how aggressive the cancer is, and therefore whether surgery is necessary.

More than 40,000 men are diagnosed with prostate cancer each year in Britain, and over 10,000 die of it.

Around one in four with prostate cancer will have an aggressive form of it, says Dr Hayley Whitaker, lead scientist on the Cancer Research UK Biomarker (which develops new ways to diagnose cancer). This means their cancer is fast growing and likely to spread elsewhere, requiring some form of treatment. 'For the rest, the disease will come to nothing and grow very slowly and they don't need treatment - they will eventually succumb to something else,' she adds.

Those with low risk, slow growing cancers can be monitored quite safely, with several PSA tests a year, and MRI scans and biopsies every year or so, without the need for immediate treatment, adds Marc Laniado, a consultant urologist at Frimley Health NHS Foundation Trust and Windsor Urology.

The challenge is distinguishing slower growing tumours from the more dangerous ones. Until now this has been done by examining tissue samples taken during a biopsy to see how abnormal the cells look and how disrupted the tissue appears.

From this a Gleason score of between six and ten is given to indicate how aggressive the cancer is. However, this can be inaccurate because it gives only a partial picture, explains Mr Laniado.

'And until a few years ago men with small tumours and low Gleason scores were having treatment because knowing that these scores could be inaccurate, doctors were being cautious.'

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John paid around £1,200 and his results showed his cancer was not aggressive (picture posed by model)

Studies have since shown that low-risk tumours do not particularly benefit from treatment. And biopsies help doctors select patients suitable for monitoring (known as active surveillance).

Now a new test offers another way of predicting how aggressive a cancer is - and how urgent it is for men to go through potentially damaging surgery. Called Prolaris, the test is used with existing results from PSA tests, the Gleason score and the biopsy to give a clearer likely prognosis.

It uses tissue already taken in a biopsy. But rather than looking at the structure of the cells, it examines the cancer in greater detail, adding chemicals to break open the cells and extract the DNA.

Scientists then examine 31 genes and the proteins they produce, which are thought to trigger the abnormal cells to divide and grow quickly.

 Prolaris is very exciting because we are now in a better position to judge whether to proceed with treatment

By determining which of these genes are switched on and active, researchers can determine how aggressive a cancer is likely to be.

'Prolaris looks at the activity of the cancer cells, and is very exciting because we are now in a better position to judge whether to proceed with treatment,' says Mr Laniado.

The test - only available privately - costs around £1,200. John decided to pay for it himself and a week later his results showed his cancer was not aggressive and was slow growing.

'Many patients, like John, are in the middle range of risk because he had a low Gleason score but a large volume of tumour, on both sides of the prostate, so alongside the other evidence, Prolaris helped us make a decision about his treatment,' says Mr Laniado.

Dr Whitaker suggests more evidence is needed for the test.

There have been 11 studies worldwide, which examined old tissue samples using Prolaris to see if the test's prediction matched what actually happened to the patients. Dr Whitaker says these have been 'a mixed bunch'; some are too small to be meaningful.

'What is lacking is a large study involving thousands of patients that is prospective (rather than looking back at evidence that already exists) to confirm its utility in the UK and not just the U.S.' This is because in the UK men do not routinely have PSA screening so prostate cancer patients tend to have higher grade tumours and higher Gleason scores.