An exciting article in the Guardian published last year and a confirming article published this month state that new diagnostic technology has shown ‘impressive results’. This test can spot tumors in the early stages of cancer, even before symptoms appear.
The new blood test has enough accuracy to qualify as a screening test that detects disorders or diseases in healthy individuals who do not exhibit any disease symptoms. The false-positive rate is low at 1%.
The test will be investigated in a pilot study by England’s National Health Service (NHS) in the fall of 2021. The pilot study will focus on people who are at higher cancer risk and/or fifty years of age or older.
About the Test
The test can identify certain diseases that are usually difficult to diagnose, especially in the early stages. The diseases that fall into that category include pancreatic, neck and head cancer, oesophageal, plus a number of blood cancers.
The test was developed by Grail, a company based in the United States. It searches for chemical changes in particles of genetic code that escape from tumors and leak into the bloodstream.
About Cell-free DNA
Cell-free DNA originates from DNA in the bloodstream that is not encapsulated. Part of that cell-free DNA comes from a tumor clone which is the result of a cell going a step further during cell division and emerging as a new clone.
The 2020 report in the Guardian focused on using an algorithm (artificial intelligence) that analyzes DNA shed by tumors. The DNA circulates in the blood. The targeted changes to the DNA are called methylation patterns.
Reporting Test Accuracy
The new AI-based method has an impressive accuracy level. The 2021 test was performed on 2,823 individuals who had cancer and 1,254 individuals who did not. The test found (accurately) that 5.5% of patients tested had cancer in various stages. False-positive or misdiagnoses were 0.5% of cases tested.
Detection of cancer in solid tumors such as pancreatic, oesophageal, and liver cancers where there are no other screening options was as high as 65.6%. The study’s rate of detection for stage I pancreatic cancers was 63%, but the rate was 100% positive detection for stage IV.
Positive test results of 55.1% were discovered for blood cancers such as myeloma and lymphoma. Additional test results identified the location and type of cancer including where the cancer originated.
Out of 96% of samples indicating the presence of cancer, 93% of these predictions were accurate.
First research author Eric Klein, M.D. lauded this opportunity as among the most significant in reducing the universal burden of cancer. Since the study was conducted with patients who had already received a diagnosis of cancer, the new screening methods must still be performed in actual trials prior to routine use.
Looking Forward
The study offers a glimpse well into the future of how cancer detection will look. The test results are an indication that these AI-based methods are definitely in the running as a means of detecting cancerous DNA.
The NHS results involving 140,000 individuals should be available by 2023. The clinical director of the NHS expressed his opinion that this type of blood test would help NHS to meet its goal of detecting 75% of cancers early, thus giving physicians the highest and best chance of curing their patients.
Yet the scientists are facing new challenges meaning additional studies are necessary to determine the test’s performance at actual cancer screenings.
