A more targeted form of radiotherapy – known as three-dimensional conformal radiotherapy (3D CRT) – is being tested to see if it can help people with prostate cancer to live longer.

The new technique involves building up a three-dimensional picture of the diseased part of the prostate gland with the help of computerised tomography (CT) scans. Radiotherapy is then focused precisely on the cancerous area.

Professor of Radiotherapy at the Institute for Cancer Research, The Royal Marsden Hospital, Alan Horwich, explains: In the past, we used to treat what was essentially a cube of tissue with radiotherapy. Conformal radiotherapy allows us to deliver radiation in complicated shapes to tumours. This can avoid damaging normal tissues, reducing the risk of the side effects of radiotherapy.

This means doctors can give higher doses of radiation, which are more likely to destroy the cancer, without increasing side effects.

Scans mean that we can see the cancer precisely. Then we compute the way that radiation will interact with the tissues and plan how to add together several radiation beams from different angles to pinpoint the diseased tissue and avoid the healthy tissue, says Professor Horwich.

Previous research has shown that CRT decreases acute problems, such as rectal bleeding, associated with the treatment of prostate cancer. Trials are now under way to find out if the new method will improve the long-term survival rates of patients, compared to standard radiotherapy. If this is confirmed, conformal radiotherapy is likely to become a standard treatment.

Many centres in the UK can offer conformal radiotherapy to patients with prostate cancer. Studies are investigating whether the technique is better than traditional radiotherapy for other cancers, including lung, head and neck, and oesophageal cancers.