Scientists have developed a blood test that can help predict how well patients with breast cancer will respond to specific treatments, potentially allowing doctors to tailor therapy earlier and more effectively.
The test analyses circulating tumour DNA (ctDNA) released into the bloodstream by cancer cells. In a study involving 167 patients with advanced breast cancer, researchers found that low levels of ctDNA before treatment – or after just four weeks of therapy – were strongly linked to better outcomes.
Patients with lower or undetectable ctDNA levels were more likely to respond to treatment and experienced longer periods before their cancer progressed. This was particularly striking in patients with triple-negative breast cancer, an aggressive form of the disease with limited treatment options, where low ctDNA levels were associated with significantly longer progression-free survival.
Researchers say the test could help doctors avoid giving patients treatments that are unlikely to work and instead switch sooner to alternative therapies or clinical trials. While the study focused on advanced breast cancer, experts believe the approach could also prove valuable in earlier-stage disease.
Further trials are under way to determine whether adjusting treatment based on early ctDNA results can improve long-term patient outcomes.
