I had bilateral breast cancer which was first diagnosed by MRI in 2013 (5 mm, Stage 1). Treated by bilateral mastectomy in 2015. My nonsmoking mother died of lung cancer at age 71. This large cancer probably started when she was younger than I am (age 70).
I will soon get treatment for my severe aortic valve stenosis. It seems like a good idea to make sure I don’t have cancer before investing in heart surgery.
I sent away for a Galleri blood test since this has been hyped to be able to detect 30 different cancers. Then I saw this article today.
Galleri promises to detect multiple cancers—but new evidence casts doubt on this much hyped blood test
A blood test being trialled in large numbers of people in England is facing mounting evidence against its implementation as a screening tool for early cancer.
by * Margaret McCartney, senior lecturer in general practice, freelance writer1, broadcaster and Deborah Cohen
BMJ 2024; 386
…
The NHS is currently running a £150m trial of the test, involving more than 100, 000 participants in England…
The test is one of several multicancer detection blood tests, or “liquid biopsies,” on the market and uses sequencing technology to analyse DNA fragments circulating in the blood, also known as cell free DNA (cfDNA). These cfDNA fragments from cancer cells have specific “methylation patterns.” Grail says that Galleri checks over a million methylation sites in DNA, using machine learning and artificial intelligence to detect whether someone is harbouring a cancer…
But some eight months before the NHS Galleri trial was announced in 2020, Grail published data showing that in patients already known to have cancer the test detected only 43.9% of stage I-III cancers.(https://www.bmj.com/content/386/bmj.q1706#ref-5)
In 2021 another Grail funded study in Annals of Oncology found that the test sensitivity for stage I cancers was only 16.8%…
A 2023 Lancet study suggests that the test’s sensitivity is even lower in a screening population than in previous trial populations. (https://www.bmj.com/content/386/bmj.q1706#ref-11)12 In the Pathfinder study, conducted on asymptomatic patients in North America, 1.4% had a positive test, but 62% of these results turned out to be false positives… [end quote]
The results from the large NHS trial aren’t available yet. The rest of the article discusses the finances and also the important issue of whether early detection using Galleri results in improved mortality.
If I had known of these poor results I would not have ordered the test. I will try to return it since the sensitivity and accuracy are so low that either a positive or negative result would be essentially meaningless.
Wendy