|
Women with early-stage breast cancer can avoid radiotherapy after mastectomy as it does not affect long-term survival, new research finds.
An international trial found that patients with early-stage breast cancer who underwent a mastectomy (breast removal) and were taking anti-cancer drugs had similar 10-year survival rates, whether or not they received radiotherapy.
Experts say the findings should help guide treatment discussions, as many patients may not actually need radiotherapy.
The trial was funded by a Medical Research Council (MRC) and NIHR partnership. A team at the University of Edinburgh led the study. The results published today in the New England Journal of Medicine.
Many women with early-stage breast cancer treated by mastectomy and anti-cancer drugs receive chest wall radiotherapy. The practice has long been standard to kill any remaining cancer cells and lower the risk of recurrence. But it is based on trials from the 1980s and some consider it outdated. This has left uncertainty about its benefit and variations in use worldwide.
The SUPREMO trial (Selective Use of Postoperative Radiotherapy after Mastectomy) aimed to answer this question. Experts studied the impact of chest wall radiotherapy in patients at intermediate risk of breast cancer returning.
The group included women from 17 countries with 1 to 3 affected lymph nodes. It also included women with none but who had other tumour features of aggressive behaviour that increase the chance of recurrence.
All 1,607 patients in the study underwent mastectomy, axillary surgery – removing lymph nodes from the armpit – and modern anti-cancer therapy. They were randomly assigned radiotherapy (808 women) or no radiotherapy (799).
Researchers found no difference in overall survival of patients after 10 years of follow up. 81.4 per cent of those who received radiotherapy were still alive, compared with 81.9 per cent of those who did not. Radiotherapy had no impact on disease-free survival (the length of time without any cancer returning). There was no impact on the cancer spreading from the breast around the body.
The treatment had minimal impact on cancer recurring at the site of mastectomy. In total 9 patients who received the treatment saw their breast cancer return on the chest wall. This compared with 20 who did not.
Radiotherapy side effects were mild with no excess deaths reported from cardiac causes. Better drug treatments reducing the chances of the cancer returning have helped lessen the need for radiotherapy, the team say.
But the team caution that the study only looked at those with intermediate-risk breast cancer. Patients with a higher risk of their cancer returning could possibly benefit from chest wall radiotherapy, they add.
Professor John Simpson, Director of the MRC-NIHR Efficacy and Mechanism Evaluation (EME) Programme, which funded the research, said: "It is fantastic that this long-term international clinical trial, led from the UK, has delivered high-quality evidence that was lacking in this important clinical area. The findings potentially allow patients to avoid unnecessary treatments, leading to more effective and efficient use of health and care resources.
"The trial emphasises how difficult, but really important clinical questions can be answered by broad collaboration in the research community and through public funding partnerships such as that between MRC and NIHR."
Professor Ian Kunkler, from the University of Edinburgh’s Institute of Genetics and Cancer, said: “The SUPREMO trial provides no evidence to support the continued use of radiotherapy to the area of the chest wall in most patients with intermediate-risk breast cancer who have undergone a mastectomy if they are also treated with modern anti-cancer drug treatment.”
The international research team included scientists from the UK, Netherlands, Australia and China. Funders included the European Organisation for Research and Treatment of Cancer (EORTC) and the Dutch Cancer Society. Others were Cancer Australia, Breast Cancer Institute, Edinburgh Cancer Centre and HSBC Trustees.
|