Prostate to be most common cancer

PROSTATE cancer in men is set to top the cancer league within 20 years. The rapid rise in the disease is being fuelled by the ageing of the population and increased awareness, making it urgent that a means of identifying those at risk is found, Professor Colin Cooper, of the Institute of Cancer Research, said yesterday.

Prostate cancer is the fourth commonest cancer behind those of the lung, breast and bowel. Cases of the cancer have risen by half in the UK in the last two decades to 16,000 a year, but in the US where screening is widespread they have soared three-fold to almost 200,000 cases a year.

The institute is developing a two-stage test that would not only detect the presence of the cancer, but would also identify those men in whom it was likely to progress rapidly.

The prostate is the gland at the base of the bladder which makes the seminal fluid in which the sperm swim. Despite the improved detection rate in the US there had been no fall in deaths up to 1993, the latest year for which figures were available, Professor Cooper said. That could now change. Early reports from North America suggested there had been a fall in deaths and in cases of advanced disease over the last five years.

"If it turns out that screening leads to a reduction in deaths in the US there will be overwhelming pressure to introduce the test here. Potentially that could create a problem for us which is why we need to find a gene marker."

Signs of prostate cancer can be detected by a blood test known as the PSA (prostate specific antigen) test, but this gives no clue as to how fast the cancer is likely to grow. Only one in five men who test positive for PSA will go on to develop life threatening disease and two NHS studies have rejected the introduction of PSA screening in the UK on these grounds.

Professor Cooper, who is to head the first Centre for Urological Sciences in the UK to be built at the Institute, said that using silicon chip technology to identify gene markers for the disease, it should be possible to predict which men had the most aggressive form of the cancer.

He said prostate cancer was perceived as a disease of old men and attracted only pounds 1 million of research funding for every pounds 16 million spent on breast cancer. However, one in 20 cases ran in families with strong genetic link and could affect men in their 40s.

The cause of the cancer is not understood but is thought to be linked with diet. The incidence is six times higher in the US than in Japan, but Japanese men who emigrate to the US quickly acquire the American rate.

A vaccine against cervical cancer, which could end the need for screening against the disease, is undergoing preliminary tests in humans.

Dr Judy Deacon, an epidemiologist at the institute, said animal studies had shown that vaccination can prevent infection with the human papilloma virus which causes genital warts and is known to be present in almost all cases of cervical cancer. But it would be ten years before it was available.