Before You Book That Full-Body MRI, Make Sure You Haven't Skipped The Most Important Cancer Screening Test

Walk through any airport bookstore or scroll through social media for a few minutes, and you'll see it everywhere: longevity. People are tracking sleep, wearing continuous glucose monitors, measuring hundreds of biomarkers, optimizing VO₂ max, and, increasingly, paying thousands of dollars for executive physicals and full-body MRI scans.

As a colorectal surgeon, I actually appreciate this trend. For the first time, many people are thinking proactively about their health instead of waiting until they become sick. But I worry that many are overlooking one of the most effective—and proven—tools we have to prevent cancer. That tool isn't a full-body MRI. It's colorectal cancer screening.

Detection vs Prevention

This is the distinction that often gets lost. Most health screening aims to detect disease after it has already developed. Colonoscopy is different. It can actually prevent cancer. The majority of colorectal cancers develop from precancerous polyps over many years. During a colonoscopy, those polyps can be identified and removed before they ever become cancer. Very few screening tests can honestly make that claim. That's why colonoscopy occupies a unique place in preventive medicine. It doesn't simply look for cancer: it interrupts the process that creates cancer.

Colorectal Cancer Is Changing

For decades, colorectal cancer was considered a disease of older adults. Unfortunately, that is no longer true. In recent years, colorectal cancer has become one of the fastest-rising cancers in younger adults. In response to this trend, national screening guidelines now recommend that average-risk adults begin screening at age 45 instead of 50. As a surgeon, I wish I could say this change was simply precautionary. Unfortunately, it reflects what many of us have been seeing in practice for many years. More patients in their 40s—and sometimes even younger—are presenting with colorectal cancer.

So Where Does Full-Body MRI Fit?

This is where nuance matters. I am not against magnetic resonance imaging (MRI). MRI is an extraordinary diagnostic tool. When someone has [just to name a few] neurological symptoms, liver disease, orthopedic injuries, indeterminate findings on CT or ultrasound, or a known medical condition, MRI can provide life-changing information. The question is different when we're talking about healthy people with no symptoms. Currently, there is no high-quality evidence showing that routine full-body MRI screening improves survival or reduces mortality in average-risk individuals. In fact, major radiology organizations do not currently recommend whole-body MRI as a general screening test for healthy adults. That doesn't mean MRI is "bad." It also certainly doesn't mean that doctors are keeping the good tests from their patients to keep them sick (or other crazy online narratives). It simply means that enthusiasm has outpaced evidence.

The Problem With Chasing Rare Diseases

Human psychology naturally draws us toward finding rare, hidden diseases. A full-body MRI feels comprehensive. It feels like you're looking everywhere. But the most important screening tests aren't necessarily the ones that examine the largest number of organs. They're the ones that have been proven to improve outcomes.

Play out a scenario. Say a healthy patient, friend, or family member approached me and explained they had done extensive bloodwork which was all normal, exercised routinely, followed a healthy diet, and had a healthy sleep schedule. And then they asked me what else I would recommend to optimize their preventative health maintenance. And even if they told me there were no financial barriers for them. I would absolutely recommend colonoscopy over full body MRI. Why? Because it is an intervention proven for decades through innumerable studies to reduce colorectal cancer deaths. While routine MRI may be reassuring, but has not been shown to prevent cancer deaths (and in many populations, has not even been shown to increase cancer detection).

The Wellness Hierarchy

If your goal is longevity, think of preventive health as a pyramid. The foundation consists of interventions supported by decades of evidence:

• Don't smoke.

• Maintain a healthy weight.

• Exercise regularly.

• Control blood pressure.

• Don't drink alcohol (or at least minimize it).

• Manage cholesterol when appropriate.

• Complete age-appropriate cancer screening.

Only after those boxes are checked should you begin asking whether advanced testing such as executive physicals or full-body MRI will meaningfully improve your health. Too often, people spend thousands of dollars searching for uncommon diseases while skipping one of the most effective cancer prevention strategies available.

My Advice to Patients

If you're investing in your health, I'm all for it. In fact, I absolutely love how focused this generation is on it. But start with the interventions that have consistently been shown to save lives. If you're 45 or older, talk with your physician about colorectal cancer screening. If you have symptoms such as rectal bleeding, unexplained weight loss, persistent changes in bowel habits, anemia, or a family history of colorectal cancer, don't wait for your routine screening age—seek evaluation sooner. The newest technology is not always the most important. Sometimes the most powerful innovation is the one we've had for years, backed by decades of evidence, that quietly prevents cancer before it ever has the chance to begin.