Are Findings From a Trial Started 30 Years Ago Still Relevant Today?
“Clearly the treatment of early breast cancer has advanced since the 1980s when the Scottish Conservation trial was launched,” study coauthor Ian Kunkler, MB, FRCR, of the University of Edinburgh, said in a written comment. “There is more breast screening, attention to clearing surgical margins of residual disease, more effective and longer periods of adjuvant hormonal therapy, reduced radiotherapy toxicity from more precise delivery. However, most anticancer treatments lose their effectiveness over time.”
He suggested that more trials are needed to confirm the present findings and reiterated that the lack of long-term recurrence benefit is most relevant for patients with disease features that predict late relapse, who “seem to gain little from adjuvant radiotherapy given as part of primary treatment.”
Dr. Kunkler noted that the observed benefit in the first decade supports the continued use of radiotherapy alongside anticancer drug treatment.
When asked the same question, Freedman emphasized the differences in treatment today vs the 1980s.
“The results of modern multidisciplinary cancer care are much, much better than these 30-year results,” Dr. Freedman said. “The risk for local recurrence in the breast after radiation is now about 2%-3% at 10 years in most studies.”
He also noted that modern radiotherapy techniques have “significantly lowered dose and risks to heart and lung,” compared with techniques used 30 years ago.
“A take-home point for the study is after breast conservation, whether or not you have radiation, you have to continue long-term screening mammograms for new breast cancers that may occur even decades later,” Dr. Freedman concluded.
How Might These Findings Impact Future Research Design and Funding?
“The findings should encourage trial funders to consider funding long-term follow-up beyond 10 years to assess benefits and risks of anticancer therapies,” Dr. Kunkler said. “The importance of long-term follow-up cannot be understated.”
This study was funded by Breast Cancer Institute (part of Edinburgh and Lothians Health Foundation), PFS Genomics (now part of Exact Sciences), the University of Edinburgh, and NHS Lothian. The investigators reported no conflicts of interest.
A version of this article first appeared on Medscape.com.