REDWOOD CITY, Calif., July 21 (San Francisco News Online) — A recent Fox News story about an unnamed former “Bachelor” contestant who said a preventive scan found a brain tumor before symptoms has renewed interest in full-body MRI. For most healthy adults, though, major medical groups still do not recommend the scan as routine screening.
The key question for everyday decision-making is not whether MRI can sometimes find a problem early. It can. The question is whether scanning the whole body in people without symptoms does more good than harm. The Food and Drug Administration says it knows of no scientific evidence showing that whole-body scanning of people without symptoms provides more benefit than harm.
What is a full-body MRI?
A full-body MRI is a magnetic resonance imaging scan that looks at large parts of the body in one session. Unlike CT scans, MRI does not use ionizing radiation, the American Cancer Society says. That makes it appealing to some people who want to avoid radiation exposure.
Some companies market full-body MRI as a way to look for cancer, heart disease and other hidden problems. Prenuvo says its scan can detect more than 500 conditions, including cancerous tumors at an early stage.
Why are doctors cautious?
The American College of Radiology says there is not enough evidence to recommend total-body screening for people with no symptoms, risk factors or family history suggesting disease. The American Academy of Family Physicians also recommends against routine full-body scans for early tumor detection in people without symptoms. The American College of Preventive Medicine says doctors should not use whole-body scans for that purpose.
A JAMA editorial by Matthew Davenport, a University of Michigan radiology professor, and Dr. Scott Reeder said no major medical group recommends whole-body MRI for the general population because the benefits remain unproven. The U.S. Preventive Services Task Force gives 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 can go wrong?
The main concern is not just what the scan finds, but what happens next. The American Cancer Society says whole-body scans can show “spots” or “shadows” that turn out to be normal variations in the body. Those incidental findings can lead to more imaging, biopsies, procedures, stress and cost.
Doctors also warn about false positives, when a scan suggests a problem that turns out not to be one, and overdiagnosis, when a scan finds a condition that would never have caused major symptoms or death. Cleveland Clinic says false negatives are also possible, meaning a scan can miss something important and give false reassurance.
UCSF radiology researcher Rebecca Smith-Bindman said there is “not a stitch of evidence” that the scan helps people live longer or better. She also warned that false positives can lead to more testing that may not help the patient. Davenport said the harms can come from “invasive testing or surgeries or follow-up of findings that are of uncertain benefit.”
What about cost?
The American Cancer Society says insurance companies rarely pay for full-body MRI because it is not part of standard medical care. That means many people who choose the scan are likely paying out of pocket.
What should a reader make of the brain tumor story?
A story about a tumor found on a preventive scan can sound persuasive, especially when it involves a serious diagnosis caught before symptoms. But the broader medical guidance has not changed: for people who feel well and do not have a known risk factor, routine whole-body MRI is still not recommended by the FDA, the ACR, the AAFP or the ACPM.
For San Francisco readers, that debate is especially relevant because UCSF clinicians and researchers are among those warning about the limits of the test. The bottom line from the available evidence is not that full-body MRI is useless. It is that, for most healthy adults, the scan has not been shown to improve outcomes enough to outweigh the risks of false alarms, follow-up testing and added cost.
