The NHS will be piloting a new blood test developed by GRAIL, that may be able to identify over 50 types of cancers. The trial will begin in mid-2021 on 165,000 patients. The test works by detecting molecular changes in the blood caused by cancer in people who may not have any obvious symptoms. It may be able to identify cancers that are typically difficult to detect early, such as head and neck, ovarian, pancreatic and some blood cancers. If successful, this test will allow cancers to be detected and diagnosed in their early stages when they are more likely to be curable. Currently, in England, around 50% of cancers are diagnosed at stage one or two (early stage), but the NHS Long Term Plan is to increase this to 75% by 2028. This test will hopefully allow the NHS to meet that goal, and in turn, improve the overall mortality from cancer.
What are the implications of these results?
If the results prove effective, by 2024 and 2025 the test may be rolled out to an even larger population. In fact, by 2028, if it is successful in detecting cancers in asymptomatic people, the blood test could be used as a national screening programme, available to everyone. Is this a good idea? What may be the effect of any false positive or false negative results on the population? Could this cause unnecessary anxiety or false reassurance? Who may not want to take this test? Should it only be given to people who are at risk of cancer (e.g. if they have a family history of cancer)? Does the possibility of early detection and treatment of these cancers override any drawbacks?
The impact of COVID-19 on cancer diagnosis
During the pandemic, there has been a significant decrease in screening for cancers as services were put on hold. There was also a decrease in the number of people diagnosed/referred for cancer as many patients who may have had symptoms didn't visit their GP or go to the hospital due to fears of COVID-19. What impact may this delay have on these patients? Does this information change the importance of this blood test in any way?
Read about the preliminary trials of this blood test: https://www.annalsofoncology.org/article/S0923-7534(20)36058-0/fulltext
Read about cancer services during COVID-19: https://scienceblog.cancerresearchuk.org/2020/09/11/whats-happened-to-cancer-services-during-the-covid-19-pandemic/