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Breast health 2020

A blood test to detect the earliest signs of breast cancer

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Professor Nicholas Turner

Professor of Molecular Oncology, The Institute of Cancer Research

A liquid biopsy involves taking a blood sample from a cancer patient before, during and after a course of treatment. Testing for cancer cells and cancer DNA in the bloodstream is showing huge promise as a way of monitoring breast cancer and how it responds to treatment – helping guide clinical decisions.

Researchers at The Institute of Cancer Research, London, have pioneered the development of so-called ‘liquid biopsies’ – blood tests that can detect the spread of cancer more quickly than other current methods.

These blood tests look for cancer cells and tiny pieces of cancer DNA that are circulating in the blood. In this way, liquid biopsies can detect the return of breast cancer after treatment before patients develop symptoms or secondary tumours become visible on scans.

This enables researchers and clinicians to identify the earliest signs of relapse before the patient clinically relapses, which they hope will improve patient outcomes by staying one step ahead of cancer.

More efficient and less painful for patients

Professor Nicholas Turner is Professor of Molecular Oncology at The Institute of Cancer Research (ICR) and Head of the Ralph Lauren Centre for Breast Cancer Research at The Royal Marsden NHS Foundation Trust.

As a Team Leader in the Breast Cancer Now, Toby Robins Research Centre at the ICR, he specialises in the use of liquid biopsies to deliver more precise treatment for breast cancer patients, leading many national and international trials.

We are already showing that liquid biopsies are not only giving us new insight into how cancer develops – they are already starting to improve treatment.

“Liquid biopsies look for tumour cells or DNA in the bloodstream and represent a major step forward in our ability to monitor a cancer and how it responds to treatment,” he explains.

“Previously, the only way to get detailed genetic information about tumours was to take a tissue biopsy either during surgery or through the use of a needle – and because that can be painful for patients, there is a limit to how many times it can be done.”

Faster insights into the effectiveness of treatments

Liquid biopsies can act as a biomarker – a biological measure – to indicate whether treatment is working and how a cancer is responding. To effectively treat cancer and prevent it from coming back, spotting when drugs have stopped working is key. By detecting the earliest signs of relapse, liquid biopsies may indicate when a patient needs to change to another drug.

By analysing the genetic changes in the tumour DNA found in the blood, researchers and clinicians can also pick out patients who may be particularly likely to respond to certain drugs or who are likely to relapse after initial treatment – enabling them to select and target further treatment at those who would benefit.

“We are already showing that liquid biopsies are not only giving us new insight into how cancer develops – they are already starting to improve treatment by guiding clinical decisions, leading to better outcomes for breast cancer patients. In fact, they can even help us match patients to certain treatments.”

Opening abilities to match patients more precisely to treatments

“Our ongoing plasmaMATCH trial looks at identifying mutations in metastatic breast cancer of individual patients to try to match them to specific targeted treatments. Initial results are promising and have already shown that genetic changes in a small group of breast cancer patients could be targeted with certain drugs, suggesting that liquid biopsies could be a better way of guiding treatment than standard tissue biopsies.”

Liquid biopsies are simple blood tests which are being tested in many other clinical trials too. Despite still being evaluated in the laboratory and the clinic, these tests are likely to be introduced more widely in cancer management in the future.

Hopefully in a not too distant future, liquid biopsies will replace standard, invasive biopsies and help improve treatment for breast cancer patients.

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