Scientists in the UK have unveiled a groundbreaking new blood test that can predict how effectively a patient with breast cancer will respond to a specific treatment, potentially transforming care pathways for millions.
A Game-Changer for Personalised Treatment
The research, led by a team at the Institute of Cancer Research (ICR) in London, focuses on a 'liquid biopsy' that analyses tiny fragments of cancer DNA circulating in a patient's bloodstream. This circulating tumour DNA (ctDNA) offers a real-time snapshot of the disease.
The study involved 167 patients with advanced breast cancer. Blood samples were taken before treatment began and again after just four weeks of therapy. The results revealed a powerful link: patients with lower levels of ctDNA at the start, or whose ctDNA became undetectable quickly, responded far better to treatment and saw their cancer kept at bay for significantly longer.
Key Findings from the Clinical Trial
The trial split participants into two key groups. One group had cancers with specific mutations and received targeted therapies. The other had triple-negative breast cancer, an aggressive form constituting 10-15% of global cases, and received a combination of two drugs.
For the triple-negative group, the results were stark. Those 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%.
In the mutation-targeted group, patients whose ctDNA was undetectable after four weeks of treatment saw their cancer controlled for 10.6 months versus 3.5 months for those where it remained detectable.
Transforming Patient Outcomes
Dr Iseult Browne, the study's first author and a clinical research fellow at the ICR, emphasised the test's potential. "Knowing this at the earliest stage means we can avoid giving patients drugs that won't work and provide them with alternatives before their cancer has a chance to grow," she stated.
This could mean swiftly switching to an alternative targeted therapy, a different drug combination, or enrolling a patient in a clinical trial for a novel treatment. Trials are now underway to confirm if adapting treatment based on this early blood test improves long-term outcomes.
Professor Nicholas Turner, a professor of molecular oncology at the ICR and consultant at The Royal Marsden NHS Foundation Trust, highlighted the broader implications. "This research looked at advanced breast cancer, but these tests could also work for early-stage breast cancers," he said, noting its potential to make treatment "faster, more personalised and ultimately more effective."
The study was funded by Breast Cancer Now, Cancer Research UK, the NIHR Biomedical Research Centre at The Royal Marsden, and the ICR.
