REDWOOD CITY, Calif., July 21 (San Francisco News Online) — A preventive full-body MRI can sound like a simple way to catch trouble early. But for most people without symptoms, major medical groups say it should not be treated like a routine screening test.
The Food and Drug Administration says it knows of no scientific evidence that scanning people without symptoms offers more benefit than harm. The American College of Radiology, the American Academy of Family Physicians and the American College of Preventive Medicine all say routine whole-body MRI screening is not recommended for the general population.
In San Francisco, where UCSF experts are part of that national debate, the question matters because elective scan companies are marketing the test as a way to find disease before it causes symptoms.
What is a full-body MRI?
MRI stands for magnetic resonance imaging. It uses magnets and radio waves to create pictures of the body. The American Cancer Society says MRI does not use ionizing radiation, unlike CT scans.
Some companies say a full-body MRI can detect hundreds of conditions, including cancer at an early stage. But that claim is not the same as proving that the scan helps people live longer or healthier lives.
Why are doctors cautious?
The main concern is that a scan can show something that looks abnormal but turns out to be harmless. The American Cancer Society says these findings can look like “spots” or “shadows” that are normal variations in the body.
That can lead to more tests, more scans and sometimes procedures that turn out not to be needed. It can also cause anxiety while people wait for answers.
UCSF radiology researcher Dr. Rebecca Smith-Bindman said there is “not a stitch of evidence” that the scan can help people live longer or better, and she warned about false positives and follow-up testing. In a JAMA editorial discussed by ABC News, University of Michigan radiologist Matthew Davenport and Dr. Scott Reeder said the benefits remain unproven for the general population.
The American College of Preventive Medicine says doctors should not use whole-body scans for early tumor detection in people without symptoms. 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 suggesting disease.
The U.S. Preventive Services Task Force also gives pancreatic cancer screening in asymptomatic adults who are not known to be at high risk a D rating, which means the harms outweigh the benefits.
What are the downsides?
Experts point to several possible harms: false positives, incidental findings, overdiagnosis, overtreatment, unnecessary follow-up tests, false reassurance if a problem is missed, and high out-of-pocket cost.
The American Cancer Society says insurance companies rarely pay for full-body MRIs because they are not part of standard medical care. WebMD has reported that scans can cost about $2,000 or more and are usually not covered by insurance.
The American Cancer Society says the risk often comes from the downstream effects: a scan may turn up a questionable finding that leads to more testing even when nothing serious is wrong.
Why do some people still want one?
A scan that finds a hidden problem can sound reassuring, especially after a high-profile report about a preventive scan that uncovered a brain tumor. But one striking case does not prove that routine screening helps the average healthy adult.
That is the core of the medical debate. The FDA says it knows of no evidence that whole-body scanning of people without symptoms provides more benefit than harm. Until that changes, major medical groups say the test should remain outside routine screening for people who are otherwise well.
For now, the choice is less about a miracle test and more about whether a person is prepared for what the scan can and cannot tell them: sometimes a useful clue, sometimes a false alarm, and often a bill to match.
