A Scan a Day Keeps the Doctor Away?
Should we all do annual whole body cancer scans? There is currently a growing market of private imaging centres offering a wide battery of tests including full body scans - as a preventative or pre-emptive tool - for patients who aren’t considered at high risk, or showing any symptoms. Full body scans are increasingly being used as a diagnostic method with which doctors can detect cancers, cardiovascular risk and other modifiable or actionable issues as early on as possible. Given the buzz around body scans, not a week goes by without one of our patients asking if they should get a full body scan ‘’just in case’’. The answer, however, to who is a good candidate for a full body scan is rather complex and merits some very careful considerations:
1. Knowing is better than hoping: Without any indication of disease or discomfort in the body, we generally go about our days in hope that our bodies are functioning well. However, there may be dormant conditions in the body, the early detection and treatment of which can prove to be lifesaving. However, a full body scan is not the only, and oftentimes not the most effective method of collecting that knowledge. Knowledge amassed through comprehensive regular health checkups–although collected through expert examination, multiple investigations and tests, instead of one single scan–can be more specific, less invasive, more cost-effective, and equally or more revealing of your health condition.
2. The truth can hurt: In a study conducted by the Department of Radiology at the University of California, 1000+ healthy middle-aged adults went through a full-body scan, and the scans uncovered an average of 2.8 abnormalities each. Over a third of them needed a follow up. Whole body scans can unearth even the tiniest of benign abnormalities, or ‘incidentalomas’ - harmless cysts on your lungs, livers, pancreas to name a few. In the medical world, if something isn’t the textbook definition of ‘normal’, doctors will want to investigate. Further investigations mean more follow up tests, possibly surgeries, unnecessary anxiety, and even death. The question to ask yourself before going for a full-body scan without symptoms is if you’re ready to find out about the smallest of abnormalities in your body which may or may not become a reason for concern in the future. The technical term for Victims of Medical Imaging Technology is VOMIT. However, this is a highly contentious and derogatory term which has no standing in personalised medicine guided by professional judgement and unclouded by commercial incentive.
3. Timing is everything. It’s not whether to scan, but when. Work out - risk-adjusted to your predisposition of a given cancer or disease - when in your life and just how often to test. This includes your genetics, keeping a track of your family health history, especially of cancer, or conditions that can lead to cancer. It is vital to estimate your cumulative risk exposure to risk factors such as tobacco, alcohol, radiation, and other environmental toxins. Computational approaches are replacing expert opinion and standardised pathways including C the Signs and AbTrace that are helping decide if it is better to test for cancers earlier or more frequently in life, or how safe it is to wait.
4. Earlier is not always better: Paradoxically, early detection while always leaving more time for treatment, but does not necessarily mean a better or longer life: The biggest advantage of any early detection method is that you have more time to be treated. However, that doesn’t always mean that people live longer or better as a result of finding out earlier. For some conditions it may just mean that you get treated for longer and die at the same time. For example, there was a wide scale screening programme for thyroid cancer in South Korea that detected 15 times more cases than previous tests. However, there was no net improvement in death rates from increased testing. So the biggest advantage in this case is to the hospital system being paid to treat you or the drug company, not the patient.
Care for a scan today, Sir?
The decision to do a full body scan is not simple, complicated by the advertising and messaging around these services that ride off the success of the occasional cases when full-body scans have genuinely saved lives. How do we make such decisions with our patients? Today, this needs ongoing consultation with experts.
Prof. Anwar Padhani and Prof. Mu Ko are widely acknowledged as the leading lights in whole body Diffusion Weighted MRI (DWI) research. DWI is fascinating, fast, and doesn’t need injected contrast. There is no radiation either, though CT (which uses high doses of irradiative x-rays) can see things that MRI cannot. A full-body DWI cleverly picks up a particular intensity of resonating water molecules in cells which turns out to be higher in faster growing tissue like tumours. This can, with the right kit and eyes, reveal very small tumours down to 3mm - which often means it’s at surgically curable early stage. Companies like Prenuvo, EZRA and Preventicum have built whole businesses around this. We are lucky enough to work directly with the leading lights out there, but their research has been implemented globally with DWI relatively accessible in many major cities. And their personal excellence is also being emulated by AI to help take the guesswork out of whether it’s an okay mass or something that looks fine but is certainly not okay. Even the gut, notoriously hard to analyse, is being decoded by the likes of our brilliant friend Brandon Whitcher, PhD with neural networks that far outperform the image analysis tools of just a few years ago.
We have been geeking out on this stuff for nearly a decade ourselves having conducted and funded research, advised and invested in this AI Radiology space with ventures like EZRA, Klarismo, Mindshare Medical, Khieron and Lucida. So we have biases, for sure. Notwithstanding those, whole body MRI is certainly not something we embark on lightly or automatically for all.
Full Body /Whole Body MRI is generally not a freely available thing in medicine. The profession doesn’t take healthy, low risk people and go looking for things in the whole body; only certain parts like the breast at landmark intervals. Especially as you get older you will find things on scans that are completely benign, that you can’t just forget about. One approach is to rescan to see how it changes. Another is to dive in and discover what it is. Such investigations are invasive. A needle or surgery is often required with anaesthetic, and rare, serious and fatal errors and side effects all occur all the time during this procedure. And because the number of innocuous lumps and bumps in your organs are so high, age 50 onwards, it turns out the overall number of accidents and deaths in healthy people is en par with the number of things you catch at stage one and can swiftly cure. There is the argument for catching someone at stage 2 or 3 say, but it turns out your survival is not significantly longer for many cancers once at that stage. Just the length of time you’re treated for. Sadly, the cancers that will most likely be the hardest to treat are also the fastest to grow.
As our friend Prof. Azra Raza explains in The First Cell, you cure cancer not by treating it but by catching it in its earliest form. Stage Zero as it were. From Zero to Stage 3 can happen in under a year for the most worrying of cancers. So to catch these you’ll need to scan more than annually. What do you do then to get everything super early? Bi-annually? Quarterly? Then how many benign and transient blobs will we need to stick harmful needles into? It’s impossible to catch everything that can catch fire or go bang on a plane even if you scan everything every time.
Our head of Internal Medicine, Dr Jim Brown, is a respiratory specialist of 20 years who has seen a scan or two. He points out that if you scan all those at high risk of lung cancer without symptoms of cancer the cure rate for treatment if you found something was twenty percent higher. The same goes if you find something completely coincidently when imaging something in that bit of the body. This may support the ‘for’ side of the argument for asymptomatic screening of your whole body irrespective of risk or symptoms, but the arguments against are abundant.
In a recent case a patient of ours had an ache in their body worse after exercise and a scan that revealed fat mass between two bones. A subsequent regular (not DWI) MRI reinforced that looked benign. The team was suspicious so followed up with a PET scan using a special tracer that showed extremely high metabolic activity normally associated with an aggressive soft tissue cancer called Sarcoma. This was alarming, and anxiety provoking for all, not least the patient and their family. After curating a brilliant surgeon who used keyhole robotics with live frozen-section histology during the operation to ensure clear margins, the tumour was out completely. However, such Sarcomas are normally followed by arduous and damaging cytotoxic ‘chemotherapy’ and radiotherapy. Analysis under the microscope from the removed tumour by a second pair of eyes, a professor of Sarcoma histology, identified this as an extremely rare benign Pseudo-Sarcoma. It is incredibly unusual - it’s benign but shines up bright on PET scans and to most histologists passes as a malignant cancer. In this case, no treatment was needed and in fact the lump could well have stayed in place without the risky operation (had it not been causing discomfort). This is one of those cases that shows just how nuanced cases often are. Ideally we need to get tissue biopsies not just images. This is invasive. But with the advent of blood based ‘liquid biopsies’, like Galleri and many others, that can find cancer DNA and RNA circulating in the blood shed by cancer cells, we can make better decisions about whether to scan or what to do after a scan without invasive biopsies or surgery. We are single-digit years away from making non-invasive ultra early cancer detection feasible for most cancers, and hopefully not too far away from this being generally affordable.
MRI machines are extraordinary advances but you can’t just use them without a team of (still mostly human) intelligences navigating the nuance, and getting the timing right. Without bright minds working with brilliant machines we deem whole body MRI scanning to be a wasted wonder, and potentially more harm than good. It is only with careful planning and the world’s leading researchers that we undertake whole body cancer screening for patients, agnostic to the providers and technologies out there. At time of writing, and it is not until now, age 48, that I am planning my first scan for this year.
A key element of aviation safety and modern aircraft flying a peculiarly huge number of miles at great speed for so many years is to catch the cracks well before the airframe breaks and catch things that can go boom before they make it on board. Both the aviation and healthcare industry benefit from extraordinary imaging technologies, and humans already have an armoury of less-nauseating, non-radiating rays and other near-magical ways of peering into our bodies and into our futures than for aircraft or hand-luggage. Choosing wisely, or computing rationally, the right time and place to get a whole body MRI scan as part of a rational ultra-early detection programme is vital for healthy longevity as cancer remains one of the grand challenges of living ever longer lives.