Circulating tumour DNA for cancer management

Cancer incidence is increasing worldwide and in the UK it is estimated that 1 in 2 people born after 1960 will be diagnosed with some form of cancer in their lifetime. New tests that analyse circulating tumour DNA (ctDNA) in patients with cancer have the potential to transform the management of the disease.

What is ctDNA?

Cells can release fragments of their DNA into bodily fluids such as blood and urine, known as cell-free DNA. Circulating tumour DNA (ctDNA) is cell free DNA that is specifically from tumour cells. Analysing ctDNA identifies if there are any genetic changes driving the growth of the cancer. Measuring the amount of ctDNA present can also provide information on the status of a patient’s cancer during or after treatment.

As ctDNA is found in the blood, this information can be gathered in a relatively non-invasive manner, for example through a standard blood draw procedure.

Listen to our podcast episode where Ofori Canacoo speaks to Dr Joanna Janus about the prospects of using ctDNA for cancer detection.

How could ctDNA tests be used in cancer management?

ctDNA is showing great promise as a biomarker to enable precision medicine, by allowing patients to receive treatments most suited to their individual cancer type and status. It is hoped that ctDNA tests could transform cancer management in multiple ways, including:

• As a ‘liquid biopsy’ to match patients to therapies based on the genetic profile of their tumour, as an alternative to tumour tissue biopsies
• To identify if any cancer remains after surgery, to help clinicians decide whether patients need additional ‘adjuvant’ therapy or extra surveillance
• For longer term monitoring of patients with stable disease, to make sure that action can be taken if there are signs the cancer is coming back
• During treatment, to understand as early as possible if the treatment is working and should be continued, or is not working and should be changed
• Screening asymptomatic people for cancer, so more people can be diagnosed earlier
• Enabling more rapid diagnosis in patients with vague symptoms where it is uncertain if the cause is cancer

Read our introductory briefing note to find out more about ctDNA testing technologies and how they could improve cancer management.

Use of ctDNA testing in non-small cell lung cancer

Currently ctDNA testing is being used in a subset of lung cancer patients with non-small cell lung cancer (NSCLC), as a liquid biopsy to enable more eligible patients to access specific targeted therapies. Our report Developing effective ctDNA testing services for lung cancer assessed the opportunities and challenges encountered during the broader implementation of this test. 

Broadening use of ctDNA testing

We want to make sure that the healthcare system learns from areas where ctDNA testing is already being used, to ensure it is implemented effectively and efficiently in the future, in order to bring the greatest benefits to patients.

We are investigating ctDNA testing technologies, the cancers in which they could have an impact, and the most pressing issues that are affecting implementation of ctDNA testing within the health system. Our current work includes:

• Reviewing the current use of ctDNA testing in lung cancer and identifying the requirements for further use of ctDNA testing to select targeted therapies in other cancers
• Bringing together experts from a wide range of relevant fields to discuss the most promising applications for ctDNA testing other than as an alternative to a solid biopsy, focussing on residual disease detection and adjuvant therapy selection, and monitoring for signs of recurrence and treatment response
• Identifying the evidence needs and other requirements for more novel uses of ctDNA testing within the health service, to allow these to be anticipated and planned for in advance, facilitating a smoother implementation of tests demonstrated to be useful.