MedicalResearch.com Interview with:
Dr Hongchao Pan PhD
Medical Research Council Population Health Research Unit
Clinical Trial Service Unit & Epidemiological Studies Unit
Nuffield Department of Population Health
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: We’ve known for a long time that recurrences can occur late in women with oestrogen receptor positive breast cancers. Our study aimed to assess how big the risk was for women who had taken endocrine treatment (tamoxifen or an aromatase inhibitor) for 5 years, which greatly reduces the risk of recurrence (by about a half during treatment and one third for the 5 years after stopping). We also wanted to find out what factors influenced the risk of recurrence, and whether some women had such a low risk that they could safely stop hormonal treatment after 5 years or, conversely, whether other women had a particularly high risk so it would make sense for them to keep on taking hormonal treatment.
What we found by following the progress of over 60,000 women who had stopped hormonal treatment at 5 years is that the risk of the cancer spreading stays about the same for the next 15 years. This risk is much higher for women whose breast cancer had spread to the nodes when first diagnosed but even for those with the best outlook (no spread to the lymph nodes and small tumours), there was a 10% chance of cancer spread over 15 years.
MedicalResearch.com: What should clinicians and patients take away from your report?
Response: The risk is likely to be somewhat lower now than it was when the women in our study were diagnosed – up to 40 years ago – as treatments such as chemotherapy have improved since then. But, nevertheless, women and their doctors should be aware of the ongoing risk and consider whether to carry on with endocrine treatment beyond 5 years.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: We need to better understand the process whereby cancer can remain dormant for so long and then spread to other parts of the body so we can work out ways to stop this happening.
MedicalResearch.com: Is there anything else you would like to add?
Response: The research was funded by Cancer Research UK and was made possible by a collaboration between clinical trial researchers worldwide, called the Early Breast Cancer Trialists’ Collaborative Group.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
N Engl J Med 2017; 377:1836-1846
November 9, 2017DOI: 10.1056/NEJMoa1701830
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