Prostate cancer survival boost

Recommendation to increase radiation doses

Increasing the doses of radiation given to prostate cancer sufferers could dramatically increase the number of lives saved, say researchers.

By giving significantly higher doses of radiation to patients with the most aggressive form of the disease, if picked up early, 79% of men remained cancer-free for at least five years.

This compares to a normal recurrence rate of around 50% for patients who have their prostates removed or receive low doses of radiation therapy, say the researchers at the University of Michigan Comprehensive Cancer Center.

The findings were welcomed by Dr David Dearnaley, who is leading a more wide-ranging study into the treatment in the UK, who said the results were "believable".

I completely go with the excitement about this technique. The figures they are giving are certainly believable

Dr David Dearnaley, Institute of Cancer Research

The high dose radiation technique involves better targeting of the cancer tumour so less tissue is affected by the radiation dose.

The prostate is a small, walnut-sized gland situated near the bladder in men which produces one component of semen.

There were 16,700 new cases of prostate cancer diagnosed in the UK in 1998 but if found early, while still confined to the gland itself, chances of survival are excellent.

In the Michigan study, doses were significantly increased from the conventional level of 66-70 Gray, up to 80 Gray.

The X-ray treatment was used on 180 high-risk tumours after taking high-resolution images to plot the best angle for the radiation dose, reports the International Journal of Radiation Oncology, Biology and Physics.

This so-called 3-D conformal radiation therapy allows doctors to avoid disease-free bladder and hip tissue.

'Tissue unscathed'

Dr Howard Sandler, a radiation oncologist at the University of Michigan, said: "This delivers a combined dose of radiation powerful enough to kill cancer cells, even though the individual beams leave nearby normal tissue relatively unscathed."

He added: "This new evidence of an advantage from higher doses not only validates the use of the approach in this subgroup of high risk patients, it also hints strongly that lower-grade tumours could be vulnerable to increased radiation delivered with careful planning."

Dr Dearnaley, reader in prostate cancer studies for the Institute of Cancer Research, is co-ordinating a Medical Research Council (MRC) study into the treatment in the UK.

He said the results of the MRC trial would be more conclusive than the Michigan study, because it uses randomised controls.

"When these results are in it will be very much easier to say we have now proven that this technique does give benefits to patients."

But he added: "I completely go with the excitement about this technique. The figures they are giving are certainly believable."

The treatment could now be given at half of the radiation units in the UK, whereas only two - The Royal Marsden Hospital in London and Christie Hospital in Manchester - were able to do so just four years ago.