Scientists have developed a simple blood test that can predict how well breast cancer patients will respond to specific treatments. The test analyses circulating tumour DNA released into the bloodstream by cancer cells, allowing doctors to gauge treatment effectiveness before or shortly after therapy begins.
Researchers studied blood samples from 167 patients with advanced breast cancer, taken before treatment and again after four weeks. Low or undetectable levels of tumour DNA were strongly linked to better responses and longer periods with the cancer kept under control.
The results were especially clear in patients with triple-negative breast cancer, where low tumour DNA levels were associated with significantly longer progression-free survival and higher response rates. Similar patterns were seen in patients receiving targeted therapies matched to their cancer’s genetic mutations.
Researchers say the test could help patients avoid ineffective treatments and switch earlier to alternatives or clinical trials. Trials are now under way to confirm whether changing treatment based on early blood test results improves patient outcomes.
