Prostate cancer cases may treble in next decade

Prostate cancer will overtake lung cancer to become the most common form of the disease among men within the next three years, scientists said yesterday.

But there is still no accurate way of detecting the life-threatening forms of the disease, which kills 9,500 men in Britain each year, experts from the Institute of Cancer Research said.

Cases of prostate cancer have doubled in the past 25 years because of the ageing of the population. The disease now affects one in 20 men.

More than 22,000 new cases are diagnosed each year. But during the next decade this could double or even treble, as more men have tests for early signs of the disease.

The trend meant that by 2006, prostate cancer would be more common than lung cancer, rates of which had fallen with the decline in smoking, the institute said.

Despite the "escalating incidence" of prostate cancer, doctors still have no way of telling which men will require treatment for aggressive forms of the disease.

Unlike most other cancers, at least 70 per cent of prostate tumours are dormant, while the remainder could become life-threatening. But the existing blood test, which identifies prostate-specific antigens (PSA), cannot differentiate between cell changes that are aggressive and those which are benign.

At present, many men have surgery or radiotherapy, which can result in impotence or incontinence, because they do not want to take the risk of a tumour growing.

But researchers at the institute are now running trials, in collaboration with the Royal Marsden Hospital, Surrey, which they hope will lead to new ways of managing the dangerous forms of the disease.

Professor Colin Cooper, head of the institute's male cancer research centre, said: "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."

Under the trials, men with raised levels of PSA will undergo "active surveillance", with regular examinations and a prostate cancer biopsy every two years. At the first signs of a tumour progressing they will be treated.

Dr Chris Parker of the institute said early results from a similar trial in Canada showed two-thirds of men could avoid treatment altogether.

"Prostate cancer is unlike any other form of cancer," he said. "It is extraordinarily variable in its behaviour. It can be life-threatening, killing about 10,000 men a year in the UK. But it can also sit around and do nothing, so it is common for men with prostate cancer to live until a ripe old age and die of something else."

The uncertainty poses a dilemma for men over 50, for whom the PSA test is available. If they had the dormant form, it was probably better not to know, but if it was aggressive they needed treatment, Dr Parker said, adding: "We are confident that a lot of men do have prostate cancer but don't know about it. If more men start to have PSA blood tests, the incidence could go up to 40,000 or 50,000 cases a year in the next five or 10 years."

The Department of Health said funding for prostate cancer research had increased fourfold in recent years.

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