Blood test can predict most effective breast cancer treatment, study finds

Scientists have developed a simple DNA blood test that can predict how well breast cancer patients will respond to treatment. The test analyses circulating tumour DNA in the blood and can indicate treatment success before therapy begins or after just four weeks. In a study of 167 patients with advanced breast cancer, low or undetectable DNA levels were strongly linked to better responses and longer periods before disease progression. The findings suggest doctors could avoid ineffective therapies, switch treatments earlier and personalise care. Researchers say the approach could improve outcomes and may also be applicable to early-stage breast cancer.