A revolutionary blood test that can predict the most effective treatment for breast cancer patients has been developed by scientists in London, potentially transforming care for millions.
How the Simple Blood Test Works
The test, developed by a team at the Institute of Cancer Research, London (ICR), is a type of liquid biopsy. It analyses tiny fragments of cancer DNA, known as circulating tumour DNA (ctDNA), which are shed by tumours into a patient's bloodstream.
In a study funded by Breast Cancer Now, Cancer Research UK, and others, researchers took blood samples from 167 patients with advanced breast cancer. They measured ctDNA levels before treatment began and again after just four weeks of therapy.
The findings were striking. Low levels of ctDNA at the start of treatment were strongly linked to a better response and longer periods where the cancer was kept under control.
Personalising Treatment from the Start
Dr Iseult Browne, the study's first author, explained the significance. "Our study shows that a simple blood test measuring circulating tumour DNA can provide an early prediction of whether a patient's breast cancer will respond to treatment," she said.
"Knowing this at the earliest stage – in this case, at the start of treatment, or after just four weeks – means that we can avoid giving patients drugs that won't work and provide them with alternatives before their cancer has a chance to grow."
For example, patients could swiftly be switched to an alternative targeted therapy, a different drug combination, or enrolled in a clinical trial for a novel treatment.
Significant Improvements in Survival
The research split patients into two groups. One group had targetable mutations and received matched therapies. The second group had aggressive triple-negative breast cancer and received a combination of olaparib and ceralasertib.
In the triple-negative group, patients with low pre-treatment ctDNA levels had a progression-free survival of 10.2 months, compared to just 4.4 months for those with higher levels. The treatment response rate was 40% versus 9.7%.
After four weeks of treatment, the results were even more telling. Patients whose ctDNA became undetectable saw their cancer controlled for much longer—12 months versus 4.3 months in the triple-negative group.
Professor Nicholas Turner, a professor of molecular oncology at the ICR, highlighted the broader potential. "This research looked at advanced breast cancer, but these tests could also work for early-stage breast cancers," he said, adding that the liquid biopsy promises faster, more personalised, and more effective treatment decisions.
With over two million people diagnosed with breast cancer globally each year, this simple blood test represents a major step forward in the fight to personalise cancer care and improve outcomes.
