Image: Metastatic breast cancer courtesy of Ed Uthman on Flickr. License: CC BY 2.0
A personalised blood test for women with early breast cancer could detect the return of the disease nearly eleven months earlier than hospital scans, a new study at five UK hospitals has found.
The study, funded by Breast Cancer Now and other collaborators, found that the test for levels of cancer DNA circulating in the blood detected the return of the disease after treatment on average 10.7 months before patients developed symptoms or secondary tumours became visible on scans.
The test, developed by scientists at The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, was found to work in all types of breast cancer, and could detect the early signs of the spread of the disease around the body (outside of the brain).
Further research is now needed to understand how the test could be used in the clinic to help guide treatment and improve patient outcomes, with UK trials now underway to assess new treatments alongside the test in triple negative breast cancer.
Who is the test for?
Breast cancer is the UK’s most common cancer, with around 55,000 women and 350 men being diagnosed each year in the UK.
While more women are now surviving the disease than ever before thanks to research progress and advances in NHS treatment, recurrences are still common and happen when breast cancer cells survive initial treatment and grow into new tumours.
In cases where the disease returns and spreads to form tumours in other parts of the body, known as metastatic or secondary breast cancer, while it can be controlled for some time it unfortunately cannot be cured. Almost all of the around 11,500 women and 80 men that lose their lives to breast cancer each year in the UK will have seen their cancer spread.
‘Liquid biopsies’ ― blood tests that can detect cancer DNA in the bloodstream ― have emerged as an exciting new field in cancer research in recent years. The tests aim to monitor how a patient’s cancer is responding to treatment in real-time, detect emerging resistance to treatment and spot any recurrences at the earliest possible stage.
Analysing cancer DNA to predict recurrence
In a new prospective study of 101 women across five UK hospitals, scientists led by Professor Nicholas Turner in the Breast Cancer Now Research Centre at The Institute of Cancer Research (ICR) assessed the potential of a new personalised blood test to detect recurrence in patients diagnosed with early breast cancer who had no signs of secondary tumours.
The tests are tailored to the make-up of each woman’s tumour to enable the levels of cancer DNA in their bloodstream to be monitored.
By analysing cancer DNA from tumour samples collected before treatment, the researchers identified mutations that could distinguish cancer DNA from all other DNA in the blood and could be tracked over time. Overall, in the 101 patients, 165 different trackable mutations were found, with 78 participants having one trackable DNA mutation and 23 patients having multiple mutations.
Blood samples were collected from participants every three months during their first year after treatment, and then every six months for up to five years thereafter.
To assess the test’s ability to detect recurrence at a molecular level in different breast cancer sub-types, the researchers combined the data with a previous proof-of-principle study to establish a bigger cohort of 144 patients.
At follow-up of approximately three years, 29 of 144 patients had seen their breast cancer return. 23 of these 29 patients had cancer DNA detected in their blood prior to relapse, with the ‘liquid biopsies’ spotting the signs of recurrence on average 10.7 months before their clinical diagnosis.
'A new treatment paradigm for breast cancer'
With the test accurately indicating the return of breast cancer across all major subtypes, the authors suggest that upcoming trials could lead to “a new treatment paradigm for breast cancer”, in which therapy could be offered at the first signs of relapse at a molecular level, rather than at a later stage once symptoms have appeared.
In addition, the researchers also conducted a sub-analysis of 80 patients who had blood samples taken at their diagnosis – with circulating cancer DNA being detected in 41 of these women. These patients were found to be 5.8 times more likely to experience a relapse during the first three years after treatment than those without detectable levels of cancer DNA prior to treatment – demonstrating that the test may also have prognostic potential in the future.
The study is published in JAMA Oncology and was largely funded by Breast Cancer Now, with additional support from The Royal Marsden Cancer Charity and the NIHR Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and the ICR.
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Professor Nicholas Turner, Professor of Molecular Oncology at The Institute of Cancer Research, London, and Consultant Medical Oncologist at The Royal Marsden NHS Foundation Trust, said:
“These new blood tests can work out which patients are at risk of relapse much more accurately than we have done before, identifying the earliest signs of relapse almost a year before the patient will clinically relapse.
“We hope that by identifying relapse much earlier we will be able to treat it much more effectively than we can do now, perhaps even prevent some people from relapsing. But we will now need clinical trials to assess whether we can use these blood tests to improve patient outcome. We have launched the first of these studies already, and hope to launch large studies in the future.”
'Extremely exciting' potential
Dr Simon Vincent, Director of Research at charity Breast Cancer Care and Breast Cancer Now, which funded the study, said:
“This could be a really significant breakthrough. The potential of this blood test to in future spot the signs of breast cancer returning or spreading much earlier in NHS clinics is extremely exciting.
“But we now need upcoming trials to identify whether offering treatments to patients at this stage could actually help intervene and improve their chances of survival or quality of life.
“The fact that these tests are personalised to each patient to try to find out whether any cancer cells remain and are on the move is unique. But for thousands of women, a blood test like this and the hope of new treatments to stop the disease returning just cannot come soon enough. The fear of breast cancer coming back can have a major impact on patients’ lives, and we urgently need to do more to support them, as well to increase awareness of the signs and symptoms of secondary breast cancer.
“While most aches, pains or coughs won’t mean the cancer is back, we’d encourage all women to report any new, unexplained or persistent changes to their GP or breast care team. Anyone feeling worried about their breast cancer returning can call our free Helpline on 0808 800 6000 and speak to one of our nurses.”