A new, simple blood test could transform breast cancer treatment by accurately matching women to the right therapies and tracking the disease's evolution, potentially eliminating the need for invasive biopsies, researchers suggest.
This innovation addresses a critical challenge: breast cancer's diverse forms each demand specific treatments, yet around one in five advanced tumours can alter their type, rendering existing therapies ineffective.
Known as the Breast Circulating Methylation Assay (BCMA), the test works by detecting tumour DNA released into the bloodstream by cancerous cells.
Experts suggest this technology's potential extends beyond breast cancer, offering a promising diagnostic tool across numerous other cancer types.
A study by researchers at The Institute of Cancer Research, London, analysed 191 blood samples from 86 patients with breast cancer.
They compared the results to two tissue samples taken on average more than five years apart.
Breast cancer switched type in 19 per cent of the samples and the BCMA test was almost 90 per cent accurate in pinpointing this change.
Nicholas Turner, a professor of molecular oncology at The Institute of Cancer Research, London, and consultant medical oncologist at The Royal Marsden NHS Foundation Trust, said: “Treating breast cancer based on its type is the mainstay of breast cancer management but until now, a tissue biopsy has been required to detect that type, and biopsies are generally only taken at diagnosis.
“Cancers can adapt and evolve, and if we continue treating it based on its initial form, we are unlikely to succeed.
“Unfortunately, we know that around 20 per cent of advanced breast cancers do switch type, and this is a major source of treatment failure if it isn’t identified.
“Our research is the first to show that it is possible to identify breast cancer’s type from a blood test – meaning that any changes to this type can be tracked easily over time, and treatment can be altered if necessary.”
Dr Nida Pasha, clinical research fellow at the Institute of Cancer Research, London, added: “Our test detects unique patterns in the tumour DNA circulating in a patient’s blood to pinpoint the exact breast cancer type.
“This can guide treatment decisions, so the next stage for this research is to assess the test in prospective clinical trials to see if it improves patients’ outcomes by tailoring their therapy.
“The technology behind this test isn’t limited to breast cancer – it could be applied across many cancer types.
“I’m excited about a future where non-invasive blood tests like this could become the norm, guiding many more cancer treatment decisions.”
Elsewhere, for almost one in 10 samples (8 per cent), biopsies showed cancer had switched type, while the blood test showed both types of cancer were present at the same time.
Researchers suggests this means some patients could benefit from two specific drugs at one time to fight the disease.
Prof Kristian Helin, chief executive of The Institute of Cancer Research, London, said: “We have long moved past treating a cancer based simply on its place of origin – breast cancer is a whole family of diseases which all require different treatment strategies.
“But treatment resistance is one of the biggest problems we want to overcome as cancer researchers. Identifying when a cancer is likely to stop responding to a particular treatment is crucial.”
Around 11,500 women die from breast cancer in the UK every year.
The study was funded by Breast Cancer Now, Wellcome Trust, and Cancer Research UK, and has been presented at the San Antonio Breast Cancer Symposium.
Dr Simon Vincent, chief scientific officer at Breast Cancer Now, added: “This innovative blood test – developed by our researchers – has the potential to transform how we monitor and treat breast cancer, ensuring people receive the most effective therapies as early as possible.
“While we need further research and clinical trials before this test can be used in routine care, these early results are hugely promising.”
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