The ABC-Bio trial tests how the next generation of molecular diagnostics can offer more treatment options for patients with metastatic disease and how a blood test (liquid biopsy) might be able to replace the more traditional biopsy that can be difficult and unpleasant.

In this study, a biopsy of the tumour from each patient is taken and undergoes gene sequencing to identify the mutations present. A blood test is also analysed for mutations in the circulating tumour DNA (ctDNA). If the results are the same this will mean that women with metastatic breast cancer will not have to endure repeat tissue biopsies but can be monitored by blood tests. If genetic alterations are identified they could potentially be targeted with therapy.

Recruitment to the study was fast and sequencing frequently successful and revealed a diversity of mutations. There is good concordance between the genetic alterations found in tissue samples and the blood. It will be important to know how many patients have their treatment plans changed as a result of this trial. It is by knowing this and the value of the liquid biopsy that it could be recommended as an alternative to an invasive biopsy for patients with advanced breast cancer.

Dr Fribbens and the team presented some of this work at the San Antonio Breast Cancer Symposium in December 2017.