UK research has shown that a blood test is able to identify various mutations in advanced breast cancer and can thus match women to targeted treatment, adding further weight to evidence backing use of liquid biopsies for more personalised cancer care.

Researchers working on the plasmaMATCH trial say the blood test is now "reliable enough" to be used in NHS patients once it has passed approval, “raising the prospect of a major reshaping of care that could speed up access to the best available drugs”.

A team at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust, analysed blood samples from more than 1,000 women with breast cancer that had returned following treatment or metastasised, to determine whether the blood test could improve treatment for women whose breast cancer is driven by one of a variety of rarer mutations.

They were able to reliably detect mutations found in tumour DNA that had been shed into the bloodstream of women with advanced breast cancer, and then matched patients to targeted treatments according to the specific mutations in the tumour DNA.

The researchers looked at three targetable defects in genes called HER2, AKT1 and ESR1, known to drive breast cancer, then gave 142 women with these mutations experimental drugs targeting the specific characteristics of their cancer.

Women with ESR1 mutations were treated with fulvestrant, while those with HER2 mutations received neratinib on its own or with fulvestrant. Women with AKT1 mutations were either treated with capivasertib plus fulvestrant, or with capivasertib on its own, according to whether their cancer was oestrogen receptor positive or not.

Researchers found that some women with HER2 (five out of 20) and AKT1 (four out of 18) mutations responded to treatment, indicating that liquid biopsies can successfully match patients with certain rare forms of advanced breast cancer to more effective treatments. However, the treatment targeting the ESR1 mutation was not found to be effective.

“Our findings show that simple blood tests can quickly and accurately tell us the genetic changes present in a patient’s cancer, and use that information to select the most suitable available treatment,” said study leader Professor Nick Turner, Professor of Molecular Oncology at The Institute of Cancer Research, London, and head of the Ralph Lauren Centre for Breast Cancer Research at The Royal Marsden. “Using a liquid biopsy could be particularly important for patients with advanced breast cancer, to help select the most appropriate treatment.

The plasmaMATCH trial was largely funded by Stand Up To Cancer, a joint fundraising campaign from Cancer Research UK and Channel 4, with additional support from AstraZeneca, Breast Cancer Now and Puma Biotechnology.