Doctors have developed a technique that could save thousands of men from impotence by predicting how aggressive Prostate cancer is before surgery.

At present needle biopsies, blood and urine samples are unable to predict accurately how dangerous prostate cancer is and whether it is likely to progress.

This means that thousands of men may be having unnecessary preventive surgery, with serious side effects such as impotence.

Now a study, published in the British Journal of Cancer, has outlined a simple and reliable technique which can be carried out on needle biopsy samples.

The Checkerboard Tissue Microarray (TMA) method, developed by scientists at the Institute of Cancer Research, looks for the multiple markers of various genes associated with Prostate cancer - including the E2F3 gene. “Overexpression” of E2F3 - first identified by the institute - is a marker of how aggressive cancer will be.

Prostate cancer is the most common cancer to affect men in the UK, with more than 30,000 diagnosed every year. Almost 10,000 men die from the disease each year.

Researchers said the new technique would allow them to investigate an enormous untapped resource of clinical specimens which were obtained at the time of cancer diagnosis.

This would allow them to identify markers of the cancer’s aggressiveness.

They said the technique would be pivotal in developing a test for Prostate cancer aggressiveness which may ultimately prevent thousands of men undergoing surgery.

The tissues in the prostate gland, an organ at the base of the bladder in men, are either surgically removed or destroyed through radiotherapy as a way to treat the cancer. This radical surgery can have serious side effects such as incontinence and impotence.

Professor Colin Cooper, the Grand Charity of Freemasons’ Chair of Molecular Biology at the institute, hopes to have a reliable test in place within two years.

He said: “This represents a real advance for the future management of Prostate cancer.

“Eventually we hope to be able to distinguish the tigers - aggressive tumours requiring treatment - from the pussycats - non-aggressive tumours which can be monitored for many years without treatment.

“Ultimately this could prevent thousands of men from having to undergo radical surgery, which can have devastating effects on their day-to-day lives.”

Professor Peter Rigby, chief executive of the institute, said: “This demonstrates the real progress we are making in the field of Prostate cancer research.

“Since discovering the E2F3 gene as a marker of Prostate cancer aggressiveness our research team has been committed to developing a test for the gene. The development of this technique is a significant step forward in Prostate cancer management and should ultimately improve thousands of men’s lives.”

Dr Chris Hiley, head of policy and research at the Prostate Cancer Charity, welcomed the development.

He said: “The difficulty that confronts many men and their doctors is in establishing whether a man’s Prostate cancer will be so slow-growing that he may not need treatment or whether it is potentially life threatening and he does.

“If the technique is proven, it will identify these [genetic] markers across a huge number of samples and will enable doctors to predict the behaviour of individual Prostate cancers, so that men will receive the most appropriate treatment.”