A new blood test for cancer

Cancer cells can float in a person’s blood. But finding them, in the past, used to be like “looking for a needle in a haystack”.

But new smart technology promises to detect these cancer cells easily and much early before a person develops symptoms. Detection of cancer cells at an early stage may be helpful for some patients.

A recently published study in the journal “Annals of Oncology” reports exciting results.

A Californian company called Grail has developed a blood test which seems to have a high degree of accuracy for detection of multiple cancers.

Times newspaper reports that “The NHS will begin a pilot scheme of the test with 140,000 people this year. If that is successful it will be used for millions of patients by 2025”

A word of caution though.

Just because something could be diagnosed early does not always mean that it is a good thing.

The most important thing is whether the early diagnosis can lead to better cure rates and a better quality of life.

If a test detects a cancer early but has no meaningful effect on quantity or quality of life, then it is not a good thing.

For example. Up to 80% of men have prostate cancer which can now be detected by a simple blood test called PSA. There is a good reason why we are NOT using the simple PSA test in every 80 year old.

Most 80 year old men die WITH prostate cancer rather than DUE to prostate cancer.

So why diagnose a cancer that is not causing symptoms if it is not going to make person live longer !


Times. New blood test, created by Californian company Grail, detects cancers among over-50s. Kat Lay, Health Editor. Friday June 25 2021, 12.01am, The Times.

Clinical validation of a targeted methylation-based multi-cancer early detection test using an independent validation set. E A Klein et al. Ann Oncol. 2021.

Guardian. Blood test that finds 50 types of cancer is accurate enough to be rolled out.
Diagnostic tool being piloted by NHS England shows ‘impressive results’ in spotting tumours in early stages
Blood tests’ development could help the NHS further.
Nadeem Badshah and agency
Fri 25 Jun 2021 06.00 BST

Daily Mail. NHS trials ‘holy grail’ blood test that can spot 50 kinds of cancer: Ground-breaking check that can accurately detect two thirds of deadly cancers early in healthy people could save thousands of lives a year. By Victoria Allen Science Correspondent For The Daily Mail
00:00, 25 Jun 2021 , updated 10:04, 25 Jun 2021

NHS. Should I have a PSA test?

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