Extra irradiation increases success of breast cancer treatment, finds European study
A European study has found that an extra 'boost dose' of irradiation after surgery for breast cancer decreases the likelihood of the cancer returning. The study involved following more than 5,000 breast cancer patients for 10 years. Some 12 countries and 33 European research institutes were involved, while funding came from a number of bodies around Europe and in the US. In the Netherlands alone, where project leader Harry Bartelink is based, one in nine women develop breast cancer. Approximately 80% of these women are treated with breast-conserving surgery. Traditionally, the final phase of treatment has involved whole-breast irradiation of 50 Gray units (Gy). In this study, roughly half of patients received an additional boost dose of 16 Gy. The extra dose was given immediately after the standard dose, which is delivered over five weeks. All patients were then followed over the ensuing 10 years. The team found that the boost dose led to a 40% reduction in the risk of tumour recurrence, with young women benefiting the most from the extra irradiation. Professor Bartelink explained to CORDIS News that the team needs to wait a few more years before drawing conclusions about improved survival rates. But the fact that more than 80% of the women who received the booster were still alive after 10 years is obviously positive. The booster works in a logical way - the higher dose of radiation kills more tumour cells. Previously researchers have hesitated over increasing dosages due to fears about side effects such as fibrosis. The number of patients developing fibrosis in this study was however not high - 4.4% in the group that had the booster, compared to 1.6% in the group that did not. It is possible that a further booster could be even more effective, but the risk of side effects must be addressed fully before this can be pursued. Professor Bartelink told CORDIS News that the team is currently in the process of investigating new technology for giving patients a higher irradiation dose without endangering their health in other ways. Tools to predict sensitivity to radiation is an additional avenue of research. According to Professor Bartelink, 'The outcome of this trial has led to a worldwide change in the treatment policy for women with breast cancer.' The results of the study were published in the August issue of the Journal of Clinical Oncology.
Countries
Netherlands