Many men with low-grade prostate cancer gain no benefit from surgery or radiotherapy, according to research published today.

Even without treatment, only 1% of men aged 55 to 59 with non-aggressive prostate cancer would die within 15 years, the study found.

Radical treatment of the low-grade form of the disease, such as removal of the prostate gland, needlessly puts men at risk of suffering serious life-long side effects, including impotence and incontinence, the researchers said.

The study, published in the British Journal of Cancer, called for the development of more tests to distinguish aggressive and low-grade prostate cancer, so men could avoid unnecessary treatment.

Prostate cancer is the most commonly diagnosed male cancer in the UK, with nearly 32,000 cases reported each year and around 10,000 deaths.

Dr Chris Parker, who led the research, said most men diagnosed with prostate cancer "live out their natural span without the disease ever causing them any ill effects".

He said the findings of the study should help men diagnosed with the disease to decide whether or not to undergo surgery or radiotherapy.

"The decision whether to have radical treatment can be tremendously difficult for the patient. So, this new information on the potential impact of treatment on overall survival will be of great interest to men faced with this decision."

Dr Parker's team is trialling a new prostate cancer management system called active surveillance, which aims to target surgery and radiotherapy only at men who need it. Patients are closely monitored to see whether they require radical treatment or simply continued observation.

Many men diagnosed with even low-grade prostate cancer currently undergo surgery or radiotherapy. In older men with slow-growing tumours a "watchful waiting" strategy is sometimes employed, on the basis that they are likely to die of other causes before the cancer kills them.

Dr Parker's research also showed that radical treatments were essential for men with aggressive prostate tumours. Without treatment, up to 68% of these men were likely to die from the disease.

Chris Hiley, the head of policy and research at the Prostate Cancer Charity, said many men with low-grade prostate cancer suffered minimal or no impact on their life, longevity or health as a result of the disease.

"Clearly, some men with a prostate cancer diagnosis will always prefer an operation to cut it out or radiotherapy to treat the cancer. This new evidence shows men mustn't be left to overestimate the survival advantage that such an option would give them," he said.

"No radical treatment is without side effects and these could be impotence, incontinence and rectal problems - all could be avoided by declining unnecessary intervention."