REDWOOD CITY, Calif., July 21 (San Francisco News Online) — A recent report that a preventive full-body MRI found a brain tumor has renewed interest in these scans. For most healthy adults, though, the key question is not whether a whole-body MRI can find something. It can. The question is whether finding more things actually helps enough to make the test worth the risk, cost and uncertainty.
What is a full-body MRI?
A full-body MRI, also called a whole-body MRI, is an imaging exam that scans large parts of the body in one session. Unlike CT scans, MRI does not use ionizing radiation, the American Cancer Society says.
That difference matters, but it does not make the test a routine screening tool. 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.
Why are people getting them?
Some companies market full-body MRI as a way to look for cancer, heart disease and other problems before symptoms start. Prenuvo says its scan can detect more than 500 conditions, including early-stage tumors.
That promise has made the test popular with people looking for reassurance. But the major medical groups that have weighed in have not endorsed routine screening for the general public.
What do medical groups say?
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 that points to serious disease or injury.
The American Academy of Family Physicians recommends against 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 early tumor detection in people without symptoms of illness.
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 are the main downsides?
The American Cancer Society says the biggest risks are false positives, incidental findings, anxiety, unnecessary follow-up tests and procedures, overdiagnosis, overtreatment, false reassurance and cost.
Incidental findings are abnormalities that show up on a scan but turn out to be harmless or unrelated to the reason for the test. The problem, the society says, is that a scan can reveal “spots” or “shadows” that may simply be normal variations in the body.
The society also says insurance companies rarely pay for full-body MRI because it is not part of standard medical care.
Dr. Rebecca Smith-Bindman, a UCSF radiology researcher in San Francisco, said there is “not a stitch of evidence” that the scan helps people live longer or better. She also warned that there could be large numbers of false positives, which can lead to more testing.
Other experts have made the same point in journal commentary. In a JAMA editorial, Matthew Davenport of the University of Michigan and Dr. Scott Reeder said no major medical group recommends whole-body MRI for the general population because the benefits have not been proven.
Could it still find something important?
Yes, a whole-body MRI can sometimes turn up a real problem. But medical groups say that a single success story does not settle the bigger question of whether routine screening helps more people than it harms.
That is why the warning from the FDA and the major societies is focused on people without symptoms and without a specific medical reason to be scanned. For them, the evidence has not shown that a full-body MRI improves health outcomes.
For San Francisco readers weighing an elective scan, the practical takeaway is simple: a test that can find hidden problems is not automatically a good screening test. The decision depends on whether the likely benefit outweighs the chance of false alarms, extra procedures and paying out of pocket for care that insurance often will not cover.
