Scientists have developed a blood test that can predict how well patients with breast cancer will respond to treatment before therapy begins. The test analyses circulating tumour DNA in the blood, released by cancer cells, to indicate whether a specific treatment is likely to work.
In a study of 167 patients with advanced breast cancer, low levels of circulating tumour DNA before treatment were strongly linked to better responses and longer periods of disease control. Similar results were seen after just four weeks of treatment, with patients showing undetectable DNA levels experiencing significantly improved outcomes.
The test was effective across different breast cancer types, including triple-negative breast cancer, where patients with low DNA levels had more than double the time before disease progression compared with others. Researchers say the approach could allow doctors to avoid ineffective treatments, switch therapies earlier and improve patients’ chances of living longer with the disease under control.
Trials are now under way to determine whether adapting treatment based on early blood test results leads to better long-term outcomes.
