The test, based on liquid biopsies, has been developed by the Institute of Cancer Research in London, and trials have taken place in relation to breast cancer. In a series of studies, researchers found traces of re-emerging breast cancer eight months before any conventional test could have picked up signs of the returning disease.
Cancer can re-emerge after a tumor has been removed if a surgeon was unable to remove all of the cancerous cells. This most often occurs when the cancer spreads to other parts of the body.
The test works by screening for circulating tumor DNA (ctDNA) present in the blood. This is a form of mutated DNA.
In a short pilot study, 55 women who had previously contracted breast cancer and who had been treated were screened. In the longer term it was found that 15 women relapsed. The test revealed signs of the cancer returning in 12 of the participants ahead of conventional methods, giving the new test an accuracy of 80 percent as an early predictive tool.
With the three patients where the test did not give an early indication there was a reason, as BBC Science explains, for each patient: “had cancers that had spread to the brain where the protective blood-brain barrier could have stopped the fragments of the cancer entering the bloodstream.”
Although the results are promising, the test remains at the initial design stage. It will be some years before the test becomes a mainstay for hospital diagnosis.
The results of the pilot study are published in the journal Science Translational Medicine (“Mutation tracking in circulating tumor DNA predicts relapse in early breast cancer.”)