Screening tests especially for cancer have been promoted on the basis of saving lives. This has rarely been questioned. A large new review has done just that. The results will surprise. There is no clear evidence that screening for cancer does save lives!
How did we arrive here?
The notion of finding disease early is hard to argue with and has led to a number of screening programs supposed to do just that. In screening we do tests on people with no symptoms to see whether they have early stages of a disease (generally cancer). If found it can be treated before it gets bigger and threatens life or wellbeing.
The two best known programs are screening mammograms and the Prostate specific antigen (PSA) blood test. Advertising campaigns are run extolling people to get a simple test that could “save their lives”.
So what could possibly go wrong? Quite a lot as it turns out. Firstly the tests done need to be able to differentiate between normal variations in the human body and early disease. With both mammograms and the PSA this is not clear-cut.
The inventor of the PSA test wrote an Op-Ed piece for the New York Times a few years back. He called the test (which was devised to monitor existing cancer) as a toss of the coin when it came to screening.
Secondly finding something early is only of benefit if it changes the end outcome for the person. And last but certainly not least, the benefits need to outweigh the harms.
To which many of you will think – what harm can come from a “simple blood test”? The test itself is simple but what it can lead to is not.
The concept of over diagnosis is a relatively new one. It describes the diagnosis of conditions that are not and never would affect the health of the individual. Its rise has been driven by mass screening programs. The cost from needless surgery and complications is considerable.
These harms have been raised by various lone voices over the last five years or so. Officialdom has generally responded with a “nothing to see here” approach.
It is notable then that the release of guidelines for prostate cancer screening in Australia were expected to “lead to fewer men having unnecessary treatment”. In these seven words is the admission that men have been having needless surgery. This surgery can leave them impotent, incontinent or both. And for every three thousand men who have “a simple blood test” one will die from a postoperative complication of surgery that was not needed.
None of this is to say that it is wrong to undergo a screening test. The problem is that people have not been given all the facts. If it were any other form of consumer product, including pharmaceuticals where companies can be fined for overstating benefits and underplaying side effects, the promoters of screening would be prosecuted for false advertising.
If it were financial advice you would get a product disclosure document to read before having it. This would outline the possible risks and loss you could face as well as the potential benefits.
But ultimately, as I wrote at the start, the whole notion of screening has been built on the basis of “saving lives”. This is virtually never questioned. Yet figures show that deaths from late stage breast cancer have been unchanged in over 30 years. So while overall survival has increased this is due to better treatments and also women being treated for “cancers” that would never have manifested – not screening mammograms.
With the “saving lives” promise being seriously questioned for the first time we find that we do not know whether it does or does not. Dr Vinay Prasad of Oregon Health and Science University told Reuters, “The fact that the medical profession promoted screening so strongly, when it was always a balancing act, when it was always a personal choice, is really shameful.”
In my view if there were a strong benefit it would be apparent after the years of screening tests and the millions of people screened worldwide.
What should you do? As usual make your own choice based on your own circumstances rather than be pushed or bullied into having a test that is of questionable value.