Blood test that finds 50 types of cancer is accurate enough to be rolled out:
A simple blood test that can detect more than 50 types of cancer before any clinical signs or symptoms of the disease emerge in a person is accurate enough to be rolled out as a screening test, according to scientists. The test, which is also being piloted by NHS England in the autumn, is aimed at people at higher risk of the disease including patients aged 50 or older. It is able to identify many types of the disease that are difficult to diagnose in the early stages such as head and neck, ovarian, pancreatic, oesophageal and some blood cancers.
Scientists said their findings, published in the journal Annals of Oncology, show that the test accurately detects cancer often before any signs or symptoms appear, while having a very low false positive rate.
The test, developed by US-based company Grail, looks for chemical changes in fragments of genetic code – cell-free DNA (cfDNA) – that leak from tumours into the bloodstream.
The Guardian first reported on the test last year and how it had been developed using a machine learning algorithm – a type of artificial intelligence. It works by examining the DNA that is shed by tumours and found circulating in the blood. More specifically, it focuses on chemical changes to this DNA, known as methylation patterns.
Now the latest study has revealed the test has an impressively high level of accuracy. Scientists analysed the performance of the test in 2,823 people with the disease and 1,254 people without.
It correctly identified when cancer was present in 51.5% of cases, across all stages of the disease, and wrongly detected cancer in only 0.5% of cases.
(Score: 2) by Beryllium Sphere (r) on Friday June 25 2021, @03:28PM (11 children)
Supposed someone suggested this as a routine screening tool. For every million people screened, five thousand would get a cancer scare and some potentially invasive tests.
It might be a worthwhile tradeoff of course.
(Score: 4, Interesting) by janrinok on Friday June 25 2021, @03:51PM (1 child)
Only if it is used in isolation. But imagine this. Currently the test identifies those with early stage cancers before any other test finds them. That doesn't imply they cannot be detected by other means, only that a simple test that can be used to screen many people is now available. Doctors can make an assessment on what is now necessary - test every 3 months, 6 months, 1 year? Are there other treatments that can be completed at this stage that will significantly improve the chances of eradicating the cancer now before it gets any more advanced? It will make the diagnoses much more timely and improve the treatment and life expectancy of cancer patients.
In the event of a positive test, it isn't necessary to tell the patient that cancer has been found, merely that more testing is required using other means to confirm or disprove the results, or the same testing is necessary at regular intervals in the future. That level of expertise is already available - doctors have been giving the results of many different tests for a wide range of medical conditions in a sensitive and intelligent manner for many years. This test isn't replacing the doctor, it isn't a test that you do at home while watching the TV. But it can be of considerable use in alerting doctors to conditions that would otherwise go unnoticed.
If the test is a false positive then having additional tests at more frequent intervals for that individual will surely be better than scrapping the test altogether and denying the test to many others who would have their cancers correctly identified much earlier.
(Score: 1) by khallow on Saturday June 26 2021, @03:19AM
Given that cancer hasn't actually been found, it goes beyond "not necessary".
(Score: 3, Insightful) by looorg on Friday June 25 2021, @04:36PM (7 children)
It's not like this test is the one and only, if they find something they'll run even more tests and start to take pictures (MRI, X-Rays etc) of your insides. Better to have a cancer scare then missing it and getting a cancer surprise!
(Score: -1, Troll) by Anonymous Coward on Friday June 25 2021, @05:30PM (3 children)
You won't be smiling when they remove your testicles, one of your kidneys and impose Sharia Law after you test positive.
(Score: 1, Interesting) by Anonymous Coward on Friday June 25 2021, @05:53PM
Are you the QAnon guy?
I take it your indoctrination didn't include training for logical fallacies, such as straw man?
(Score: 2) by Tork on Friday June 25 2021, @07:25PM
Dude. Change the channel. Seriously.
🏳️🌈 Proud Ally 🏳️🌈
(Score: 0) by Anonymous Coward on Friday June 25 2021, @09:45PM
Is Sharia Law now an FDA-approved clinical treatment for cancer? When did this happen? I didn't realize that I was quite so far out of the loop these days.
(Score: 2, Insightful) by j-beda on Friday June 25 2021, @05:57PM (2 children)
It is all in the numbers. Each of those things you describe (texts, MRI, x-rays, etc.) involve some added risk. If we needlessly subject a large enough number of people to these tests, we could actually kill more people than we "save".
If the incidence of a disease is 0.00001% and the test for the disease is 100% accurate in finding it, but gives a 0.5% false positive reading, then out of a million people you will find the ten people who actually have it, along with 5000 people who have it. Will further tests and further treatment produce fewer deaths than if we had never tested in the first place? How many of those 10 people with the disease would have had serious problems with it? How many of the 5000 people will be negatively impacted? How negatively? In some cases, the extra danger of taking a few automobile trips to appointments is similar to the danger faced by not testing for the disease in the first place.
Deciding when and how to use these sorts of diagnostics tests is actually very hard. When to do breast cancer screening is hard to decide, and the recommendations are frequency being tweaked as one example. Broad blood screening for colon cancer is another one that has proven less useful as our understanding has increased.
(Score: 0) by Anonymous Coward on Sunday June 27 2021, @12:10AM (1 child)
You also have to consider that there is opportunity cost to deciding to undergo further testing. When you are undergoing further testing you are potentially denying (or unnecessarily delaying) someone else the ability to undergo further testing within a specified time because those other tests take time and there is only so many people that can be tested at a given time and so many tests you can do on someone within a given time. There are tons and tons of tests that can be conducted, it could literally take well over a lifetime to do ALL of them, and many of these tests can be time sensitive (you want to catch the problem early) so being selective is important.
(Score: 0) by Anonymous Coward on Sunday June 27 2021, @12:18AM
I think you would find this video informative
If money was no object, should you run every medical test?
Medlife Crisis
https://www.youtube.com/watch?v=7kQk9-KLPfU [youtube.com]
The point is that it's important to be selective about which tests to run. He basically goes over the same things already discussed in the comments here.
(Score: 0) by Anonymous Coward on Friday June 25 2021, @08:56PM
There is currently an issue with late diagnosis leading to extreme treatments which would have been unnecessary if the cancer was detected earlier. Various chemotherapy poisons^H^H^H^H drugs cause DNA damage (leading to additional cancers), heart damage, nerve damage (sometimes so severe that the patient permanently loses the ability to walk), etc. Radiation treatments also increase the probability of future cancers. And, these are just concerns for those who manage to live long enough to be inconvenienced by the side effects of their treatments. Many die before the long-term side effects can impact them, but these might have lived if treated sooner.
It is extremely unlikely that any treatment would be offered solely on the result of this single test. But, if it e.g., indicates pancratic cancer, perhaps an endoscopy with a side-scope to look into the pancreas will find early cancer and save the patient. It is very unlikely that any harm will come to the patient from an endoscopy.
(Score: 1, Funny) by Anonymous Coward on Friday June 25 2021, @03:47PM
Nice to see Elizabeth Holmes has found a new job.
(Score: 1, Insightful) by Anonymous Coward on Friday June 25 2021, @04:45PM (1 child)
Fist of all many cancers are benign because the patient dies of old age long before the cancer would become a problem.
But in general the three things that need to be considered are precision, specificity, and sensitivity. There is also cost (and not just monetary cost, there is the potential cost to the patient's health and their time as well. For example x-ray's may also be bad for their health).
If a test has a low false positive rate because it also has a low true positive rate (it indiscriminately says everything is negative) then it's not very useful.
Sometimes the headlines would say that this revolutionary new test detects cancer 100 percent of the time. The problem is that it also has a high false positive rate. If a test says everything is positive it is likewise useless because, while it's true it will detect a true positive 100 percent of the time, it's also giving true positive for everything that isn't a true positive. What's the point, I might as well just declare everyone is a positive.
So when considering how useful a test is we need to consider the above factors.
(Score: 0) by Anonymous Coward on Friday June 25 2021, @04:47PM
(same poster)
err ... excuse the grammatical errors.
x-rays *
Also, this comment is not intended to be a response to this specific test in the original post. It's just meant as a general guideline.
(Score: 2) by Runaway1956 on Friday June 25 2021, @07:22PM (6 children)
I hope this means creepy perverted doctors will stop having anal intercourse with men over 50.
(Score: 2) by looorg on Friday June 25 2021, @07:26PM (4 children)
What kinda doctors are you seeing? If yours uses his penis as he is giving you a prostate examination he is doing it wrong (or right if you are into that kinda stuff)
(Score: 2) by Runaway1956 on Friday June 25 2021, @07:56PM (3 children)
How sure are you what the doctor is doing back there? Did you take video?
(Score: 2) by looorg on Friday June 25 2021, @08:10PM (2 children)
No, but I like to think I can tell the difference in size between a finger in my butt and getting fucked in the ass by another man. If you can't tell the difference I have to start wondering if you are goatse-man.
(Score: 2) by Runaway1956 on Friday June 25 2021, @08:16PM (1 child)
The voice of experience.
(Score: 0) by Anonymous Coward on Saturday June 26 2021, @06:44AM
An experienced man wouldn't have to think, they would know.
(Score: 3, Informative) by Tork on Friday June 25 2021, @07:30PM
🏳️🌈 Proud Ally 🏳️🌈
(Score: 0) by Anonymous Coward on Saturday June 26 2021, @04:00AM
Does this mean this test will work as well as the probe up your backside when you can't remember what happened?
(Looking for an excuse not to have than non-experience.)