REDWOOD CITY, Calif., July 21 (San Francisco News Online) — A preventive scan that found a brain tumor can make full-body MRI sound like an easy way to stay ahead of disease. But for most healthy adults, major medical groups say the scans are still not routine screening.
The Food and Drug Administration says it knows of no scientific evidence that whole-body scanning of people without symptoms provides more benefit than harm. The American College of Radiology says there is not enough evidence to recommend total-body screening for people who have no symptoms, no risk factors and no family history pointing to disease.
That is the heart of the debate: full-body MRI can find things, but medicine still does not know whether finding more things in healthy people leads to better health.
What is a full-body MRI?
A full-body MRI is a magnetic resonance scan that images many parts of the body in one session. Companies market it as a way to look for cancer, heart disease and other hidden problems before symptoms start.
Unlike CT scans, MRI does not use ionizing radiation, the American Cancer Society says. That makes MRI appealing to people who want to avoid radiation exposure. But the absence of radiation does not mean the scan is automatically a good screening test.
Why does a single success story get so much attention?
A story about a tumor found during a preventive scan is powerful because it suggests the test may have caught a serious problem early. But specialists say one case does not prove the scan helps the broader population.
UCSF radiology researcher Dr. Rebecca Smith-Bindman said there is “not a stitch of evidence” that the scan helps people live longer or better. She also warned that there can be “tremendous numbers of false positives,” meaning results that look worrisome but turn out not to be cancer or another serious illness.
That concern is echoed in an editorial in JAMA by Matthew Davenport and Dr. Scott Reeder. They wrote that no major medical group recommends whole-body MRI for the general population because the benefits remain unproven.
What are the main risks?
The biggest risk is not radiation. It is what happens after the scan.
The American Cancer Society says full-body scans can show spots or shadows that may be normal variations in the body. Those findings can lead to more imaging, blood work, biopsies or surgery. The society says the risk comes from those downstream effects.
Doctors also worry about:
- false positives, when a scan suggests a problem that is not really there
- incidental findings, often called incidentalomas, that are unrelated to the reason for the test
- anxiety while waiting for follow-up testing
- unnecessary procedures
- overdiagnosis, or finding something that would never have caused symptoms or death
- false reassurance, when a scan misses a problem or makes someone think they are safe when they are not
The Cleveland Clinic says full-body MRI can also produce abnormal findings that may never matter clinically and can miss disease as well.
The U.S. Preventive Services Task Force has also given pancreatic cancer screening in asymptomatic adults who are not known to be at high risk a D rating, meaning the harms outweigh the benefits.
What do major medical groups say?
The American College of Radiology said in an April 2023 statement that there is insufficient evidence to justify recommending total-body screening for people without symptoms, risk factors or relevant family history.
The American College of Preventive Medicine says doctors should not use whole-body scans for early tumor detection in people without symptoms of illness.
The FDA says it knows of no scientific evidence showing that whole-body scanning of people without symptoms does more good than harm.
Taken together, those positions do not mean MRI is useless. They mean routine screening of healthy people has not been shown to improve outcomes.
What about cost?
The American Cancer Society says insurance companies rarely pay for full-body MRIs because they are not part of standard medical care. That means patients often pay out of pocket.
What should a reader make of the renewed attention?
For a San Francisco audience, the debate has local relevance because UCSF specialists are among the researchers publicly questioning the value of these scans while the market for elective preventive imaging keeps growing.
The practical takeaway from the medical guidance is simple: full-body MRI can find abnormalities, but it has not been proven to help most healthy adults live longer or better. The tradeoff is a possible early find against a real chance of false alarms, extra testing and cost.
That is why the recent attention does not change the core advice from the FDA, the ACR and other medical groups: for people without symptoms or known higher risk, full-body MRI is still not a routine screening test.
