The LIBERATE trial is investigating the accuracy of liquid biopsies as a method of screening for mutation tumour status. The liquid biopsy method uses blood tests to determine the presence of mutations in circulating tumour DNA (ctDNA) as opposed to testing tumour tissue obtained through surgery. The trial will investigate whether liquid biopsies can be used effectively to screen for a genetic mutation called the RAS mutation in patients with advanced colorectal cancer. Specialists use RAS status to help determine which treatment will be effective for the patient.
Liquid biopsies: an alternative screening method
Tumour tissue from certain patients can be difficult to access. The hospital that stores a patient’s tumour specimen may not be the same one that they are receiving treatment in. By obtaining similar information through a blood test, we may be able to determine results more quickly.
The trial could also improve the accuracy of results for some patients, says Principal Investigator Niall Tebbutt.
“Some people have two primary tumours and when you’re doing the RAS test, it’s okay if the RAS mutation status is the same in both tumours, but if they’re different, we don’t actually know what the status is of that patient,” says Associate Professor Tebbutt. “The idea is that perhaps in that situation blood testing would actually be better, because the blood is a reflection of the whole body.”
The trial will analyse the RAS mutation status of colorectal cancer patients at different points. This will determine the accuracy of liquid biopsies when compared to tumour tissue samples.
“There have been quite a lot of changes in the technology to analyse liquid biopsies,” says Associate Professor Tebbutt. “Some have pros and cons, some are more sensitive than others, and some are more expensive than others, so we’ll be testing a few different techniques to try and determine which is the best method.”
The results of the LIBERATE trial could provide more options to bowel cancer patients in the future. These results could contribute to liquid biopsies being routinely tested in addition to tissue samples. This may allow patients to determine their treatment options more quickly and with more accuracy.
The LIBERATE trial will open to recruitment later in 2018.