There is mounting evidence that the Galleri blood test to detect multiple types of cancer from a single blood sample should not be used by the NHS, according to a report in the BMJ, and its selection for large-scale trials by NHS England was based on politics rather than good science.
The investigation led by Margaret McCartney of the University of St. Andrews and investigative journalist Deborah Cohen, highlights the doubts experts have on how well the Galleri blood test being developed by US biotechnology company Grail, actually performs and whether the bar for success has been set too low. With experts believing that the current trial ongoing in the NHS is unethical. There are also questions over just how this particular blood test was selected for evaluation and if the deal between the NHS and developer Grail, signed by the previous Conservative government, is “too industry friendly”.
The Galleri blood test is reported to be able to detect more than 50 types of cancer. The test analyses DNA fragments circulating in the blood, also known as cell free DNA (cfDNA). These cfDNA fragments from cancer cells have specific “methylation patterns.” Galleri uses machine learning and artificial intelligence to analyse methylation sites to detect whether cancer DNA is circulating. The theory is that this can lead to the detection of cancer at a much earlier stage than previous tests.
Full story in The Lowdown, 18 August 2024