Scientists have developed a DNA blood test that can predict how well patients with breast cancer will respond to treatment. The test analyses circulating tumour DNA released into the blood by cancer cells and can indicate treatment effectiveness before therapy starts or after just four weeks.
In a study of 167 patients with advanced breast cancer, low or undetectable levels of tumour DNA were strongly linked to better treatment responses and longer periods before disease progression. This was especially clear in patients with triple-negative breast cancer, where those with low DNA levels had more than double the progression-free survival of others.
Researchers say the test could help doctors avoid ineffective treatments and switch patients to better options earlier, including alternative drugs or clinical trials. Trials are now under way to see whether adapting treatment based on these early blood test results improves long-term outcomes.
