When doctors scan healthy people’s whole bodies with MRI, they find cancer in about 1 out of every 80 people—but almost a quarter of those with suspicious findings never get follow-up tests, so we might be missing even more cancers than we think.

When healthy adults get a full-body MRI scan, those flagged with higher ONCO-RADS scores (4 or 5) are much more likely to actually have cancer—about 4 in 10 for score 4 and 3 in 4 for score 5.

When doctors use whole-body MRI scans on people who feel fine and aren’t sick, they find cancer in only about 1.57 out of every 100 people — so it’s not very good at catching cancer early in healthy folks.

If you get a full-body MRI scan and have no symptoms or known cancer risks, about 1 in 60 people might be found to have cancer they didn’t know about — so it’s kind of helpful, but not super reliable, for finding hidden cancers in healthy people.

There's no universal rulebook for using full-body MRI scans to check healthy people for cancer, so different hospitals do it differently—making it hard to trust the results or use them widely in doctors' offices.

When doctors use full-body MRI scans on people who feel fine, about two out of three cancers they find are in body parts that don’t usually get checked during routine screenings—so this scan might catch cancers other tests miss.