New Delhi: In a finding that could reshape breast cancer care, researchers have reported that women with early-stage breast cancer who undergo mastectomy and receive modern anti-cancer drug therapy may not need radiotherapy, as it does not improve long-term survival.
The results come from a major international study led by the University of Edinburgh, published in the New England Journal of Medicine. The trial, backed by the UK’s Medical Research Council (MRC) and National Institute for Health and Care Research (NIHR), offers long-awaited clarity on a question that has guided post-surgery treatment for decades.
For years, many women treated with mastectomy and drug therapy have also received chest wall radiotherapy to kill any remaining cancer cells and reduce recurrence risk. However, this practice was based largely on trials from the 1980s, leaving doubts about its relevance in an era of more effective systemic treatments.
The SUPREMO trial (Selective Use of Postoperative Radiotherapy after Mastectomy) was designed to address this uncertainty and assess whether radiotherapy continues to offer benefits for patients at intermediate risk of recurrence.
The trial followed 1,607 women from 17 countries who had undergone mastectomy, axillary surgery (removal of lymph nodes), and modern systemic therapy. Participants were randomly assigned to receive radiotherapy (808 women) or not (799).
After a decade of follow-up, researchers found no significant difference in survival between the two groups. The 10-year overall survival rate was 81.4 per cent among women who received radiotherapy and 81.9 per cent among those who did not. There was also no difference in disease-free survival—the period without cancer returning—or in cancer spread to other parts of the body.
Recurrence at the site of surgery was rare: only nine women who received radiotherapy and 20 who did not experienced chest wall recurrence. Side effects were generally mild, and no excess heart-related deaths were observed.
According to experts, the results suggest that routine use of chest wall radiotherapy in women with early-stage or intermediate-risk breast cancer may no longer be necessary if they are receiving modern systemic therapy.
“The SUPREMO trial provides no evidence to support the continued use of chest wall radiotherapy in most intermediate-risk breast cancer patients treated with current drug regimens,” said Professor Ian Kunkler of the University of Edinburgh’s Institute of Genetics and Cancer, who led the study.
However, researchers cautioned that the findings apply only to women with intermediate-risk disease. Those at higher risk of recurrence may still benefit from radiotherapy.
Professor John Simpson, Director of the MRC-NIHR Efficacy and Mechanism Evaluation Programme, said the study demonstrates the importance of large, collaborative research in resolving long-standing clinical questions. “The findings potentially allow patients to avoid unnecessary treatments, leading to more effective and efficient use of health and care resources,” he noted.
The international team included scientists from the UK, Netherlands, Australia, and China, with additional support from the European Organisation for Research and Treatment of Cancer (EORTC), Dutch Cancer Society, Cancer Australia, and the Breast Cancer Institute.
