Early stage breast cancer patients live longer when they have radiation therapy to the lymph nodes behind the breast bone and above the collar bone, according to new research.
Delegates attending the annual American Society for Clinical Oncology (ASCO) congress today will hear that the effect continues for 15 years and that there are no increased side effects.
Professor Philip Poortmans, head of the department of radiation oncology at the Institut Curie, Paris, France, will tell congress that the findings from the international randomised trial, carried out by the European Organisation for the Research and Treatment of Cancer (EORTC), finally settle the question about the benefit of radiation therapy for these patients.
The trial involved 4,004 patients with stage I to III breast cancer from 43 centres and the researchers found, after a median follow-up of 15.7 years, there was a significant reduction in deaths from breast cancer – 16.0% in the treatment group compared with 19.8% in the control group, and a fall in breast cancer returning among patients who had received radiation to the IM-MS nodes (24.5% vs. 27.1%).
Overall survival was 73.2% in the IM-MS group and 70.8% in the control group and 1,117 patients died during the study period.
Researchers found no increase in non-breast cancer related mortality in the IM-MS group and there was no increased level of serious complications related to the treatment. There was no difference in the incidence of second cancers, cancer in the other breast, or deaths from cardiovascular disease between the two groups.
The rate of side effects was low, most were of low grade, and many of them were only temporary.
“Our results make it clear that irradiating these lymph nodes gives a better patient outcome than giving radiation therapy to the breast/thoracic wall alone,” Professor Poortmans will tell the congress.
“Not only have we shown that such treatment has a beneficial effect on disease control, but it also improves breast-cancer related survival.”
The researchers say that patients at low risk of their cancer spreading outside the breast may be given less intensive systemic therapy to spare them side effects. In these cases, using IM-MS radiation therapy can improve their outcome by eradicating residual tumour cells in the breast/thoracic wall.
Patients at high risk of metastases, who receive systemic therapy, also benefit because the outcome can be improved by using effective locoregional treatment to eradicate disease at the site where it is most likely to be present, the researchers say.
“The results of our trial, in which the patients received appropriate systemic treatments, contradict the existence of a ‘competition’ between locoregional and systemic treatments,” says Professor Poortmans.
“Because there is a rather positive interaction between these treatments, in many patients their combination will result in an enhancement of the combined benefits.
“Advances in radiation therapy techniques and new therapies, and earlier diagnosis may increase the benefit from IM-MS radiation treatment.
“But we believe that our trial has already given solid evidence of the benefits of radiation treatment of the IM-MS lymph nodes, and we hope that such treatment will stay where it is and become where it isn’t standard clinical practice for selected patients with early stage breast cancer.”
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