Scientists have developed a DNA blood test that can predict how well patients with breast cancer will respond to treatment before therapy begins. The test analyses circulating tumour DNA released into the bloodstream by cancer cells.
Researchers studied blood samples from 167 patients with advanced breast cancer, taken before treatment and again after four weeks. Patients with low or undetectable levels of tumour DNA were significantly more likely to respond well and have longer periods before their cancer progressed.
The results were especially strong in patients with triple-negative breast cancer, where low tumour DNA levels were linked to much longer treatment effectiveness. Similar patterns were seen after four weeks of therapy.
The findings suggest doctors could quickly change treatment for patients unlikely to benefit, avoiding ineffective drugs and improving outcomes. Clinical trials are now under way to test whether using this approach to guide treatment decisions improves survival and quality of life.
