Blood Test For Cancers?

The US-based company, Grail, devised a 'simple' blood test for cancers. The test looks for fragments of cell-free DNA, leaked into the bloodstream, by tumours. These fragments are detected as changed so-called methylation patterns. As well as revealing the presence (often before signs and symptoms are apparent) or absence of cancer, the test also specifies the tissue in which the tumour is located. The test can pick up 50 types of cancer, including those of the head, neck, ovary, oesophagus and pancreas. It can also detect some blood cancers. The test has been evaluated in a study reported in Annals of Oncology (https://www.theguardian.com/society/2021/jun/25/blood-test-that-finds-50-types-of-cancer-is-accurate-enough-to-be-rolled-out). The published study looked at more than 2800 people with cancer and more than 1,250 without the disease. The test accurately identified when cancer was present in around 50% (more, with some conditions) of patients. There was an impressively low level of false positives (around 0.5%). The scientists carrying out the study, conclude the test is sufficiently accurate to be rolled out as a screen for the over 50s. In deed, the test will be piloted by NHS England in the Autumn (Fall) of 2021.