There's an engineering concept that applies directly to medicine: "the best part is no part. The best process is no process."
In clinical practice, sometimes the best test is no test, and the best treatment is to avoid an unnecessary one.
But that's not the approach that longevity clinics — which are springing up everywhere — take.
Instead, they offer an ever-growing list of tests to assess health [1].
Behind it all, the logic feels compelling. The more information gathered, the better health outcomes can be. Problems get spotted and fixed before they get worse.
But the picture is quite different in reality. More testing and more information can often lead to worse health outcomes.
The story of South Korea illustrates why.
Table of Contents
- The story of South Korea and thyroid cancer
- Full body scans and the cascade effect
- A sensible approach to screening
- Reference List
The Story of South Korea and Thyroid Cancer
Something alarming happened in South Korea after 1999. The number of people diagnosed with thyroid cancer exploded. In 1999, there were 6.3 cases per 100,000 people in the population. By 2009, that number had ballooned to nearly 48. That's more than 7 times as much [2].
An obvious question arose: what was going on that was suddenly causing so much thyroid cancer?
The answer isn't what most people expect. After careful examination of the data, researchers figured out what was driving the surge. It didn't look like more people were actually getting thyroid cancer. Instead, doctors were simply finding more cases that had been there all along — because a government-funded cancer screening initiative had led to the widespread use of ultrasound to screen for thyroid cancer [2].
So there wasn't something environmental driving up cancer rates. That's a relief. But this greater rate of detection should be a win, right? Catching cancer early is key to effective treatment. This aggressive screening program should have led to much better mortality outcomes for thyroid cancer — right?
But it didn't. Instead, mortality rates in South Korea for thyroid cancer have remained about the same [2].
In other words, there have been no better health outcomes related to thyroid cancer in South Korea, despite aggressive screening that let doctors catch many cases they used to miss.
At this point, one might think: Well, what's the loss? Better safe than sorry.
Consider this data point. By 2012, around 11,000 patients per year were having surgery for thyroid cancer. In 2001, that number was only about 1,000. But again, this had no noticeable impact on mortality. These surgeries weren't saving lives. Most of them were totally unnecessary [3].
What probably happened was that many of these cancers were so slow-growing that they were never going to cause an issue during a person's lifetime. In those instances, there's no benefit — but there are genuine harms.
During thyroid surgery, the laryngeal nerves can be accidentally cut, causing issues with speech and swallowing. There's infection risk, bleeding risk, and the lifelong need for thyroid hormone replacement.
The losses are real and well-documented in the peer-reviewed literature. A 2016 analysis in the New England Journal of Medicine found that the thyroid surgery rate in South Korea rose more than 10-fold, while mortality from thyroid cancer remained completely flat — one of the starkest illustrations of overdiagnosis in modern medicine [3].
Full Body Scans and the Cascade Effect
This isn't just a story about South Korea. It's a cautionary tale about how more healthcare doesn't always lead to better outcomes — and the latest longevity medicine fads appear to be missing this point.
Consider full-body MRI scans. These are rising dramatically in popularity. The logic sounds right: as one provider puts it, patients can "catch conditions before they become crises" [4].
It's true — a dangerous cancer might occasionally be caught. But there's also a high probability that something else will be caught instead.
When patients undergo high-precision scans like CT scans and MRIs, these instruments often uncover unexpected findings. They're called "incidental findings" when they aren't related to the reason for the scan. For instance, a patient undergoing a scan to look for calcium in the arteries might have a mass noticed in their lung — even though the lung was never the concern.
Incidental findings are extremely common. They show up in 20–40% of CT or MRI scans [5].
For a patient with no symptoms who is getting a scan as a preventative measure, everything found will be incidental. The key thing to notice: it is extremely common for these scans to reveal something.
But isn't that a great thing? Now there's awareness of a secret problem that can be addressed.
Here's the issue: what should be done? In practice, what often happens is further exploration. The initial finding triggers what researchers have called a "cascade of care" — a series of expensive additional tests and procedures, which can themselves trigger even more tests and procedures [6].
Most of the time, these incidental findings turn out to be benign. One study looked at nodules in the lung that were incidental findings in patients being scanned for plaque in their arteries. In a group of 459 people, the scan found small growths in the lungs of 81 participants, or 18% [7].
None of those growths turned out to be cancerous. Follow-up CT scans were conducted on 63 of those 81 patients. The growths had gone away in 35% of cases. In 62%, they hadn't changed. In only 2 people had the growths increased in size [7].
Here is an issue slightly different from what was happening in South Korea. Instead of a problem that didn't need to be treated, incidental findings often turn out to be abnormalities that aren't problems in the first place.
Occasionally, full-body scans do catch a cancerous growth. But here is the completely counter-intuitive part illustrated by the South Korea story: it is often the case that cancer is slow-growing and won't cause any harm if left alone. In those situations, there is no benefit from discovering it [6].
For these reasons, the logic behind full-body screening scans is flawed. The intent is to prevent harm through early diagnosis. But in many cases, the opposite happens: there is increased harm and no benefit [6].
That's why expert bodies like the American College of Radiology don't endorse full-body screening for asymptomatic patients without obvious risk factors or a relevant family history. In a statement published in 2023, the ACR stated: "To date, there is no documented evidence that total body screening is cost-efficient or effective in prolonging life…" [8].
One might think: "Can't someone just get the scan and ignore things that are likely nothing?" But consider being told by a doctor: "We found an unusual lump on your pancreas. But not to worry — the odds are very high that it's nothing." For most people, that uncertainty is extremely difficult to cope with. Many will want to find out more through further imaging and biopsies, even if the chance of a real problem is one in a million.
Similar issues appear with other diagnostic services offered through longevity clinics. One provider offers a slate of over 160 lab tests, many based on a single blood sample [9].
Some of these tests are clinically meaningful and important to check — like LDL-cholesterol levels. But for many others, the results are completely meaningless. It's marketing spin to justify a higher price.
Two more examples illustrate the problem clearly.
Prostate cancer screening. Though prostate cancer is very common, many men who have it never experience symptoms and, without active screening, would never know they have the disease [10]. This is the defining feature of clinically insignificant disease: it is present but would not have shortened life or reduced quality of life.
When cancer is diagnosed, various treatment strategies are possible — but those treatments carry significant risks of serious problems like erectile dysfunction and incontinence [10].
Even the biopsy itself carries a significant risk of adverse effects, including a slightly elevated risk of death [11].
Obviously, sometimes treatment is necessary and can save lives. But often biopsies and treatments are carried out in cases where there would not have been any problems whatsoever.
On balance, the U.S. Preventive Services Task Force concluded that there is only a small potential benefit for regular screening for men aged 55 to 69 — and there are substantial risks of harm [10].
This example also highlights another potential harm from screening: the anxiety and stress that comes from findings. Even when a finding turns out to be nothing, there can be considerable anxiety in the meantime. For many, a diagnosis of cancer is deeply distressing. In cases where the cancer was never going to cause problems, that distress is needless and could have been avoided entirely.
Even when nothing is found in screenings, the approach taken at many longevity clinics can heighten fear of disease and focus attention on inactionable information that adds nothing to actual health.
Microplastics filtering. The final example highlights the risk of spending money on unproven fixes to unproven problems. An emerging trend involves having microplastics filtered out of blood. One clinic in London charges £10,000 for the procedure [12].
Scientists aren't yet sure whether having microplastics in blood represents a clinical problem at current exposure levels. And there is certainly no established evidence that this filtering procedure fixes anything — particularly given that the procedures involve plastic tubing, which is itself a source of microplastics. Paying £10,000 for an unvalidated procedure targeting an uncertain risk is a textbook example of why consumers should apply rigorous skepticism to longevity clinic offerings.
Finally, there's the potential for significant financial harm. The magnitude varies depending on local healthcare systems. But in some places, the cascade of additional tests and procedures carries enormous costs. The initial screenings alone can be expensive: in the U.S., whole-body MRI scans can easily cost thousands of dollars [4].
A Sensible Approach to Screening
Do these risks mean there should be no screening at all? What's the right approach to guard health without unnecessary harms and costs?
A starting point is recognising that things can go wrong in either of two directions. There can be too much healthcare — aggressive screening when no symptoms are present. There can also be too little healthcare — failing to screen in situations where the benefits clearly outweigh the risks. Most people understand the logic of too little healthcare intuitively. But the logic of too much is harder to grasp. Unless you've examined examples like thyroid cancer in South Korea, it's difficult to accept that sometimes the best test is no test, and the best treatment is to avoid an unnecessary one.
The best way to balance potential costs and benefits is to take an evidence-based approach. Most common types of screening are carefully studied. There is good evidence about which screenings help produce better health outcomes and which are unlikely to. Expert bodies that study the existing evidence provide guidelines that give a solid starting point for decision-making.
For example, the American Cancer Society publishes recommendations about cancer screening. Screenings for breast cancer, colorectal cancer, cervical cancer, and lung cancer are recommended for certain populations [13].
Checking blood metrics like LDL cholesterol and Apo B is also well-supported — these are linked to heart disease by substantial evidence and are highly actionable. When levels are elevated, specific steps can be taken to change this through diet, exercise, and where appropriate, medication.
Outside of screenings supported by sound data, healthy skepticism is warranted when it comes to searching for problems in the absence of symptoms. That's where the greatest risk lies of leaving health — and finances — worse off than before.
The strongest impact on long-term health outcomes comes from what is well-established: meaningful improvements in diet and regular exercise can make a substantial difference to risks for top killers like heart disease — without the harms that come from over-investigation.
The principle from engineering holds: sometimes the best part is no part, the best process is no process. In preventive medicine, that translates to: the right test, for the right person, at the right time — guided by evidence, not by profit-driven longevity clinic menus. That approach consistently delivers better outcomes than the more-is-always-better philosophy that longevity clinics are currently selling.
Reference List
- https://www.healthylongevity.clinic/programs
- https://www.bmj.com/content/355/bmj.i5745
- https://www.nejm.org/doi/10.1056/NEJMc1507622
- https://www.prenuvo.com/
- https://www.mja.com.au/journal/2024/220/1/first-do-no-harm-responding-incidental-imaging-findings
- https://www.ajronline.org/doi/10.2214/AJR.22.28926
- https://pubmed.ncbi.nlm.nih.gov/18954846/
- https://www.acr.org/News-and-Publications/Media-Center/2023/ACR-Statement-on-Screening-Total-Body-MRI
- https://www.functionhealth.com/our-tests
- https://jamanetwork.com/journals/jama/fullarticle/2680553
- https://www.sciencedirect.com/science/article/pii/S0302283813005587
- https://www.wired.com/story/this-startup-promises-to-clean-your-blood-of-microplastics-clarify-clinics/
- https://www.cancer.org/cancer/screening/american-cancer-society-guidelines-for-the-early-detection-of-cancer.html
