Experts are aiming to develop a test to identify which prostate cancer sufferers need treatment.

A team at the Institute of Cancer Research said at least 70% of men do not need treatment, but at the moment it is impossible to tell who does and who does not.

Most go on to have treatment because they do not want to take the risk that their cancer becomes dangerous.

However treatment can have side effects such as impotence and incontinence.

The priority has to be to find a more reliable test

Shaun O'Leary, The Prostate Cancer Charity

Prostate cancer is set to become the most common male cancer by 2006, as lung cancer rates fall and the population ages.

Incidence of the cancer has been rising steadily over the last 30 years.

It now affects around 22,000 men in the UK each year and is fatal for around 10,000.

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Campaigners have raised the profile of the cancer, and more has been done to encourage men to take more care of their health.

Genetic changes

Existing testing is not failsafe. The PSA (Prostate Specific Antigen) test which is available is unable to differentiate between cell changes caused by cancer and those caused by benign changes in the prostate.

So there is a high rate of false positives, which can mean more tests and unnecessary surgery.

Scientists are hoping the Institute of Cancer research trial will lead to the development of a more reliable test.

Prostate cancer patient Peter Doe says more should be done to help men with the disease

Men will be offered a PSA test and rectal examinations at regular intervals and a prostate cancer biopsy every two years.

If during this time a man's PSA level rises dramatically, curative treatment will be given.

Researchers will also look at tumour hypoxia, which means too little oxygen reaches the tissues, which it is though could play a part in prostate cancer progression.

If they can identify which genetic changes are linked to cancer progression, scientists will be able to identify other men at high risk who display the same sequences.

A similar trial in Canada showed only a third needed treatment

Professor Colin Cooper, head of the UK's first dedicated male cancer research centre at The Institute of Cancer Research said: "PSA is a blood test which only gives us limited information.

"What we need is a laboratory test that can tell us straight away whether or not a man's prostate cancer is going to be aggressive.

"Prostate cancer research is at least ten years behind research for other major cancers, and this is largely due to lack of funding."

However, experts say after increasing steadily for nearly 20 years, the mortality rate for prostate cancer is now starting to decline.

Professor Peter Rigby, chief executive of the Institute, told the BBC doctors needed to find out more about how prostate cancer can be picked up early.

"With prostate cancer, as with all sorts of cancer, if the disease is diagnosed early, then the chances of getting a cure are much higher."

Peter Doe, a prostate cancer patient, told the BBC: "We need to do something about these men who are going to die of prostate cancer. And at the moment, we're ignoring them."

Increased awareness

Shaun O'Leary of The Prostate Cancer Charity said: "The priority, whilst there's so much doubt about whether there should be a screening programme, has to be to find a more reliable test."

Prostate cancer affects a small gland just below the bladder, which produces fluid for semen.

The majority of men with prostate cancer are aged over 60 years, with an average age at the time of diagnosis of 75 years.

But as the prostate gland is small, and close to other organs such as the bladder and bowel, unpleasant side-effects are common.

In around 60% of men diagnosed with prostate cancer, the disease has already spread to other parts of the body.

A spokesman for the Department of Health said the NHS Prostate Cancer Programme, set up in September 2000, included an increase to �4.2m per year by 2003-4 for prostate cancer research and mirrored areas of concern spelt out by the Institute.

He said: "Better markers for the detection, prognosis and treatment of prostate cancer are key to tackling this disease and improving prostate cancer services."