A blood test could help thousands of patients avoid undertaking chemotherapy each year by detecting whether all cancer cells have been eliminated post-surgery. This is part of a major new bowel cancer trial. Trials monitoring UK lung and breast cancer patients in the same manner are also underway.
Doctors estimate that around 50% of patients are entirely cured by surgery, rendering follow-up chemotherapy unnecessary. Over a thousand bowel cancer patients in the UK have signed up to take part in the study.
The blood test itself seeks to identify microscopic cancer traces, circulating tumour DNA, to ascertain whether surgery has removed all cancer cells entirely. A scan would not be sufficient as it would not be able to pick up such minuscule cancer traces.
The test, pioneered by Guardant Health, sends the samples to their labs in California for analysis, with the results returning approximately two weeks later.
The trial will also compare the survival rates of patients whose treatment was determined by the blood test as opposed to the standard-of-care chemotherapy group. This will occur over a three-year period.
Liquid biopsies are increasingly showing their immense value to clinicians, as they can reveal cancer much earlier than traditional methods. Indeed, a trial in Greece showed that liquid biopsies were able to identify cancer recurrence at least four years before it was discoverable through scanning.