https://sciencebasedmedicine.org/a-skeptical-look-at-screeni...
It's very non-intuitive but scans and tests have the potential to cause more harm than good.
From TFA:
>Overtesting has also created a new, unanticipated problem: overdiagnosis. This isn’t misdiagnosis—the erroneous diagnosis of a disease. This is the correct diagnosis of a disease that is never going to bother you in your lifetime. We’ve long assumed that if we screen a healthy population for diseases like cancer or coronary-artery disease, and catch those diseases early, we’ll be able to treat them before they get dangerously advanced, and save lives in large numbers. But it hasn’t turned out that way. For instance, cancer screening with mammography, ultrasound, and blood testing has dramatically increased the detection of breast, thyroid, and prostate cancer during the past quarter century. We’re treating hundreds of thousands more people each year for these diseases than we ever have. Yet only a tiny reduction in death, if any, has resulted.
>H. Gilbert Welch, a Dartmouth Medical School professor, is an expert on overdiagnosis, and in his excellent new book, “Less Medicine, More Health,” he explains the phenomenon this way: we’ve assumed, he says, that cancers are all like rabbits that you want to catch before they escape the barnyard pen. But some are more like birds—the most aggressive cancers have already taken flight before you can discover them, which is why some people still die from cancer, despite early detection. And lots are more like turtles. They aren’t going anywhere. Removing them won’t make any difference.
>Over the past two decades, we’ve tripled the number of thyroid cancers we detect and remove in the United States, but we haven’t reduced the death rate at all. In South Korea, widespread ultrasound screening has led to a fifteen-fold increase in detection of small thyroid cancers. Thyroid cancer is now the No. 1 cancer diagnosed and treated in that country. But, as Welch points out, the death rate hasn’t dropped one iota there, either. (Meanwhile, the number of people with permanent complications from thyroid surgery has skyrocketed.) It’s all over-diagnosis. We’re just catching turtles.
If you do a scan in someone asymptomatic and see a tumor it's oftentimes completely impossible to know if it's a "turtle" or a "bird." They can look exactly the same and we don't have a crystal ball.
By your argument, if there's no need to scan, there's no need to treat it right away either. Of course, if you are the sort of person who is prone to panic, you probably don't want to get a scan
Checking occasionally for something specific that's reasonably suspected due to symptoms is good. If you're always checking for everything, you have a high risk of finding something you don't actually have. It turns out that that risk overrides the beneficial chance of finding something real before it has any symptoms.
We get overdiagnosis and overtreatment of the population precisely because it is done at an individual level.
I would be more skeptical if there were a study showing overtreatment still happens in a population informed and wary of overtreatment.
The topic at hand is, as stated up-thread, "full body MRI scans for healthy people."
I think I remember seeing something about not doing mammogram and/or prostate screenings too often, lest they find a false-positive and do a whole bunch of followup tests and procedures that in turn keep widening the risk for complications.
So that is why it might be a okay'ish idea to do a MRI scan of the brain every 5 years or so? Depending where you live they are actually cheap and can be paid out of pocket.
In the US, studies have been shown that physicians who own shares in CT (not so much any more, as it becomes almost 'commodity') and MRI (which is a lot, manufacturers approach physicians to form imaging cooperatives) are ordering imaging up at more than 2 standard deviations from expectations.
As noted, MRIs in themselves aren't harmful. But with prices in the four digits in the US... you can easily pay off your $1.5M MRI machine in 18 months and be printing money with your over-imaging.
But that scan would be limited to the head and not cover the entire body.
I'm also not convinced that MRIs are a great, general purpose diagnostic tool, if it's not used to diagnose concrete issues. The experience of your friend, who I hope recovered from the tumor not withstanding.
Here's some articles. (Note how old these are. This isn't new advice).
http://www.bbc.co.uk/programmes/articles/15g8LGyBzYvMHpq6qNh...
> The first problem she uncovers is that detailed but general scans, such as a full body MRI or CT scan, can frequently bring to light small abnormalities which have no implications for health at all. They are the equivalent of tiny moles, freckles or scars on the outside of our body. Yet if they are picked up on a scan, then they can cause worry and further, much more invasive, testing – usually for no reason.
> The second problem that she uncovers is that even for some very specific tests, such as ultrasound of the arteries to assess the risk of stroke, the treatment available to rectify any small issues found carries very high risks to the patient. In the case of the ultrasound of the Carotid arteries in the neck, surgery to help clear any blockages would not be advised unless the patient had already had a stroke, or mini-stroke, making a test on an otherwise healthy person pointless.
http://www.independent.co.uk/life-style/health-and-families/...
> An American patient who had a whole body scan described how it threw up an early warning of lung cancer. He had a lung biopsy after a nodule was detected but it turned out to be a healed scar, posing no threat. However, the investigation involved four days in hospital, a painful procedure, several weeks of recuperation - and a $47,000 (£25,000) bill at the end.
http://news.bbc.co.uk/1/hi/health/7150583.stm
> "Full body MOTs" may often find benign abnormalities - so-called false positives - while missing real problems, said Professor Nicholas Wald, a specialist in preventive medicine.