Whole-body MRI screening: many findings, 1.4% malignancy, outcomes unknown

Design

Systematic review and meta-analysis of 17 heterogeneous, low-quality studies

Population

18,043 people having whole-body MRI without an evidence-based indication

Primary outcome

Proportion with no findings, any finding, actionable non-malignant findings and new cancer

Effect

Any finding 78.0% (95% CI 44.9 to 93.9); actionable non-malignant 14.8% (6.6 to 30.0); malignancy 1.4% (0.9 to 2.2)

This systematic review and meta-analysis pooled 17 heterogeneous, low-quality studies including 18,043 people who had whole-body MRI without an evidence-based indication.

Only 16.9% (95% CI 5.1 to 43.7) had no findings reported, while 78.0% (44.9 to 93.9) had at least one finding. Clinically actionable non-malignant findings were reported in 14.8% (6.6 to 30.0). Of those, 58.2% had further blood tests or imaging and 20.8% went on to a procedure. The prevalence of malignancy was 1.4% (0.9 to 2.2).

Clinical outcomes after finding a lesion could not be determined. The confidence intervals are very wide, reflecting heterogeneity across the studies.

The authors conclude that most such scans produce findings that are normal or need no follow-up, and that benefit is unknown. For a physician, the practical question is what to say to a well patient who asks about a self-referred scan.

• Whole-body MRI in people without an indication produced findings in most people and cancers in about 1.4%.
• About 15% had actionable non-malignant findings, and more than half of those had further tests.
• No evidence links screening MRI to better clinical outcomes.
• Explain the downstream tests and costs before a well patient pursues one.

Why it matters

It gives physicians figures to use when patients ask about privately marketed full-body scans.

Don't overread it

The studies were heterogeneous and low quality, so the pooled percentages are approximate and say nothing about benefit.

The statistics, in plain English

Intervals such as 5.1 to 43.7% mean the pooled figure is very imprecise because the studies differ so much in population and method. The proportions describe how often findings were reported, not whether finding them helped anyone.

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