REDWOOD CITY, Calif., July 21 (San Francisco News Online) — A recent case in which a preventive whole-body MRI reportedly found a brain tumor has renewed interest in scans that promise to spot disease before symptoms start. For most healthy adults, though, the bigger question is not whether a scan can ever find something early. It is whether the test does enough good to outweigh the chance of a false alarm, more testing and a high bill. The FDA 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, also called a whole-body or total-body scan, takes pictures from head to toe without ionizing radiation. Unlike CT scans, MRI does not use radiation. Companies such as Prenuvo market the test as a way to look for cancer, heart disease and other problems early, and Prenuvo says the scan can detect more than 500 conditions. The American Cancer Society says insurance companies rarely pay because the scan is not part of standard medical care.
Why do major medical groups stay cautious?
The American College of Radiology says there is not enough evidence to justify recommending total-body screening for people with no symptoms, risk factors or family history suggesting disease. 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. 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 harms outweigh benefits. In a JAMA editorial, Matthew Davenport and Dr. Scott Reeder said no major medical group recommends whole-body MRI for the general population because the benefits remain unproven.
What are the possible downsides?
The American Cancer Society says the test can turn up ‘spots’ or ‘shadows’ that may be normal variations in the body. Those unexpected results are often called incidental findings, or incidentalomas. Dr. Fuller, quoted by the ACS, said, ‘The risk comes from the possible downstream effects.’ Those effects can include false positives, anxiety, more scans, biopsies or other procedures, overdiagnosis and overtreatment. Overdiagnosis means finding a condition that would not have gone on to cause major symptoms or death, Cleveland Clinic says. A scan can also give false reassurance if it misses disease or makes people think a serious problem is less likely than it really is.
Why the San Francisco debate matters
At UCSF in San Francisco, radiology researcher Dr. Rebecca Smith-Bindman said there is ‘not a stitch of evidence’ the scan will help people live longer or better, and warned that false positives can lead to more testing. That concern matters for people who are weighing an elective scan as a preventive tool. The appeal is easy to understand: one test that promises a broad look at the body. The caution from doctors is just as simple: until better evidence shows that routine whole-body MRI helps low-risk people live longer or stay healthier, the scan may be more likely to create uncertainty than clarity.
The bottom line is not that whole-body MRI is useless. It is that major medical organizations say routine screening of people without symptoms or specific risk factors has not yet shown that it helps more than it harms.
