March 30, 2000 LONDON (The Independent) — A new form of radiotherapy treatment, using three-dimensional beams that curve around a cancerous tumor, avoiding healthy tissue, has been developed by British scientists.
The technique, which halts the spread of cancer and reduces side-effects, will initially be used to curb the spread of prostate cancer. But if trials are successful it could be used on other cancers.
Experts say it will be much more effective than conventional radiotherapy because a larger dose of radiation can be given, and it should reduce side-effects by up to 75 per cent.
Intensity modulated radiotherapy (IMRT) was unveiled Tuesday at the Institute of Cancer Research in central London, where trials are to begin on 90 patients treated there and at the Royal Marsden Hospital in Sutton, south London, who have prostate cancer that has spread to the pelvis.
The development allows doctors to shape treatment precisely to the irregular and complex shape of tumors, which wrap themselves around healthy tissue in the body.
Standard radiotherapy treatment involves geometrical beams forming a "box" around a tumor before destroying it, but that approach can damage healthy tissue and leave permanent side-effects. It also delivers single beams with the same dose of radiotherapy to every part of the tumor.
With IMRT an image of the patient's body is taken using a CT scan and the information fed into a computer to find where irradiation is most and least needed, which allows it to calculate tailor-made treatment.
The radiation beams are delivered through special robotic "leaves" which move around during treatment, allowing various doses to be given to different areas of the tumor. The technique, used successfully in localized prostate cancer, allows doctors to deliver a total dose of radiotherapy 33 per cent higher than possible with conventional treatment, and is now used in 15 centers across England.
Scientists at the Institute of Cancer Research are now trying to refine the technique to treat prostate cancer that has spread to the pelvis. Side-effects of conventional radiotherapy, such as diarrhea, bleeding and bowel incontinence are severe, preventing doctors from giving effective treatment.
Dr. David Dearnaley, senior lecturer at the institute, said: "This is a very exciting time for us. We finally have the technology to tailor radiotherapy treatment to complex 3D tumor shapes."
Copyright 2000 The Independent. All rights reserved.
