Blood tests known as ‘liquid biopsies’ could represent a major step forward in our ability to detect and monitor breast and other cancers Image Liquid biopsy study leader Professor Nick Turner, Consultant Medical Oncologist at The Royal Marsden and Team Leader at the ICR More people are surviving breast cancer than ever before, thanks to progress in research and NHS treatment, but recurrences – which happen when breast cancer cells survive initial treatment and grow into new tumours – remain common. When the disease returns and spreads to form tumours in other parts of the body – known as metastatic breast cancer – it can be controlled for some time, but cannot be cured. Indeed, almost all of the 11,500 women and 80 men who lose their lives to breast cancer each year in the UK will have seen their cancer spread. Detecting DNA However, ‘liquid biopsies’ could provide a way forward. Emerging as an exciting new field in cancer research in recent years, these blood tests could help us monitor how a patient’s cancer is responding to treatment in real time, detect emerging resistance to treatment, and spot any recurrences at the earliest possible stage. Previously, the only way to get detailed genetic information about tumours was to take a tissue biopsy, either during surgery or through use of a needle. But because the process is invasive and uncomfortable for patients, there is a limit to how many times it can be done. By contrast, a liquid biopsy simply involves taking a blood sample from a patient before, during or after a course of cancer treatment, and then testing it to detect tumour cells or DNA in the bloodstream. A recent study – published by researchers at the ICR and The Royal Marsden in JAMA Oncology, and funded by Breast Cancer Now and other collaborators including The Royal Marsden Cancer Charity and Le Cure – found that using liquid biopsies for women with early breast cancer could detect the return of the disease almost 11 months before patients developed symptoms, or secondary tumours became visible on hospital scans. The test was found to work in all major subtypes of breast cancer, and could detect the early signs of the spread of the disease around the body (outside of the brain). Further research is now needed to understand how the test could be used in the clinic to help guide treatment and improve patient outcomes, with UK trials now under way to assess new treatments alongside the test in triple-negative breast cancer. The authors suggest that upcoming trials could lead to “a new treatment paradigm for breast cancer”, in which therapy could be offered at the first signs of relapse at a molecular level, rather than at a later stage once symptoms have appeared. By identifying relapse much earlier, we hope to treat it more effectively, and perhaps even prevent it Early signs Professor Nicholas Turner, who led the study, says: “These new blood tests can work out which patients are at risk of relapse much more accurately than we have done before, identifying the earliest signs almost a year before the patient will clinically relapse. “We hope that by identifying relapse much earlier, we will be able to treat it much more effectively than we can do now, and perhaps even prevent some people from relapsing. But we will now need clinical trials to assess whether we can use these blood tests to improve patient outcomes. We have launched the first of these studies already, and hope to launch larger studies in the future.” With clinicians and researchers also working with liquid biopsies in prostate, breast, lung and gastrointestinal cancers – and more recently, head and neck cancers and paediatrics – the goal is for the technique to benefit as many patients as possible.