We all hate uncertainty, and for the last two decades radiologists and other vendors have been offering “full body scans” to detect cancer early. Initial full body scans were usually CT scans, which are associated with a small amount of radiation exposure, about the equivalent of two years of background radiation. More recently, some companies have been promoting full body MRI scans, which have no radiation exposure. Body scans have been the subject of journalistic articles in outlets including the New York Times and New York Magazine, and some of our clients have been asking whether they should provide such scans to employees.
The problem with doing screening tests on people who have no symptoms is that you need to scan many people to find an early cancer that can be cured. Along the way, scans pick up many other abnormalities which might require further testing or even surgical procedures, but discovering these doesn’t improve the person’s health or prolong their lives. Physicians talk about finding “incidentalomas,” which are diagnoses that don't matter clinically but cause extra costs and significant patient anxiety.
A 2019 literature review of a dozen studies with over 5000 asymptomatic people who received a screening full body MRI scans found that the rate of “critical” findings was quite high, and the overwhelming majority of these were not ultimately found to represent serious disease. Examples are finding cysts or lumps in the kidneys, liver or lungs which turn out not to be cancer. Only one of the included studies explicitly reported false positives, which were present in 16% of those who were scanned. The cost of doing such screening scans is the cost of the scans and the cost of any additional follow-up diagnostic care, as well as treatment of any complications.
The researchers concluded:
Based on current evidence, healthcare providers should not offer whole-body MRI for preventive health screening to asymptomatic subjects outside of a research setting. Asymptomatic subjects undergoing whole-body MRI should be informed about the substantial prevalence of critical and indeterminate incidental findings, the lack of verification data, and the apparent substantial proportion of false-positive findings.
Implications for employers:
Be very skeptical of vendors who promise that performing MRI or other full body scans on employees and members will save money.
Various types of medical scans are recommended for selected people at especially high risk of disease, where the risk of a false positive is dramatically lower. See below.
Most health plans have a proactive technology review process that will determine whether diagnostic tests are medically necessary, and employers should be cautious of directly contracting for diagnostic services that would be denied by their health plans.
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Tomorrow: Lung cancer screening is underused!