A new form of testing, called liquid biopsy, spots cancer cell presence long before traditional methodology used currently in UK hospitals, like CT scans.
The test, which is already used in prenatal studies on Down’s syndrome, works by detecting free-floating mutated DNA, which dying cancer cells release into the blood stream. A sample of blood is taken and the pathologists look for circulating cancer cells or simply for pieces of DNA from the tumour.
In a trial involving 100 lung cancer patients, the rise in blood tumour DNA was found months or even a year before relapse was officially diagnosed.
Checking for DNA fragments in a simple blood test allows Doctors to non-invasively screen for early stage cancers, to monitor for response to treatment and to monitor resistance to particular treatment. They could be used after surgery to see whether the cancer really has been completely removed.
Tests for circulating cancer cells, CTCs, have been around for a number of years, but Doctors rarely use them and patients have had to pay privately. The new tests for cell-free circulating tumour DNA, ctDNA, are causing far more excitement because the tell Doctors what is happening in real time to the tumour.
This particular study was led by Professor Charlie Swanton of the Francis Crick Institute in London. The tests were 92 per cent accurate, and such genetic testing is likely to become the new norm in the future of cancer care.