A new way of delivering radiotherapy for breast cancer can cause fewer cosmetic changes and less discomfort than conventional treatments, results from a new patient trial reveal.
Scientists funded by Cancer Research UK, The Royal Marsden Hospital and the Directorate of Health and Social Care South assessed a system called Intensity Modulated Radiotherapy (IMRT), in which doses of radiation are strictly controlled to prevent damage to healthy tissue.
IMRT has become possible following advances in physics, mathematics and tumor imaging techniques and the development of sophisticated shielding devices that can be manipulated electronically. The system employs large numbers of radiation beams directed from many different angles to create geometrically shaped, three-dimensional radiation fields. These are optimized by computers, which vary the number of beams, their direction and intensity to tailor radiotherapy to the target tissue.
The results of the trial are preliminary, but it appears that women receiving IMRT are up to 30 percent less likely to suffer shrinkage of their breasts or other physical changes compared with those treated with standard radiotherapy, according to lead researcher Professor John Yarnold.
Women diagnosed with early stage breast cancer usually have surgery to remove the tumor followed by radiotherapy of the whole breast to prevent the cancer from returning. But conventional radiotherapy, while effective, causes breasts to shrink or makes them feel lumpy and sore in some patients. Women who experience these problems may also be prone to rare, serious side effects, including rib fractures and severe muscle stiffness.
Much of this damage occurs because the doses of radiation reaching different parts of the breast vary considerably, with some areas being overdosed with radiation. IMRT is designed to avoid these problems by using sophisticated computer imaging to judge the depth and density of tissue, allowing the design and delivery of radiotherapy that gives all parts of the breast an equal, constant dose.
Yarnold, based at The Royal Marsden Hospital, comments: "Women whose breast cancers are diagnosed at an early stage have a very good chance of recovery, but damage to their breasts and related side-effects of treatment can cause serious problems for quality of life and self esteem. It's essential that we develop treatments that not only improve survival, but also aim to make the lives of survivors better."
In the trial, researchers examined women's breasts before and two years after treatment, reporting the amount of damage to breast tissue in 261 women who had given written informed consent to be randomly assigned conventional radiotherapy or IMRT.
They found that with conventional treatment, 54 percent of women suffered permanent changes to the appearances of their breasts, compared with 37 percent of women in the IMRT group.
Women were also asked to assess how they felt before and after radiotherapy. Their perceptions of breast hardness and discomfort tied in closely with the researchers' scientific judgments on breast appearance, suggesting that the benefits recorded in the trial will make a real difference to the lives of patients.
"Our results so far suggest that IMRT will have a real and positive impact on the quality of life of women treated for breast cancer and may safeguard them from a wide range of side effects," said Yarnold.
"The current trial is continuing to collect data but we hope our results so far will encourage larger-scale studies on the benefits of the new system, so that it can be introduced into clinical practice as soon as possible."
SOURCE:
Cancer Research UK (http://www.cancerresearchuk.org)
