MRIs, Mammograms and the Risk of Breast Cancer Screening Cascades of Care

By Stacie Dusetzina, PhD
May 10, 2022

Stacie Dusetzina is an associate professor of health policy at Vanderbilt University School of Medicine. Her research focuses on measuring and evaluating the costs of prescription drugs. Stacie is a member of the 2022 Tradeoffs Research Council.

Is more information always better? When it comes to health – and health screening in particular – more sensitive imaging and other tests can turn up what look like health problems but turn out to be clinically unimportant, sometimes leading to harmful and costly cascades of care.

recent paper published in JAMA Network Open and led by Ishani Ganguli, Nancy L. Keating, Nitya Thakore, Joyce Lii, Sughra Raza and Lydia E. Pace shows how this dynamic plays out for breast cancer screening, comparing care following traditional mammography versus magnetic resonance imaging (MRI). MRIs are more sensitive, which means they may be better at identifying cancer, but they also deliver more false positives and are not recommended for women at low to medium risk of breast cancer. MRIs also often pick up other things, which may turn out to be harmless but require costly follow-up tests to find out. And yet MRI screening for breast cancer has grown

In this study, the researchers analyzed data from nearly 20,000 commercially insured women 40 to 64 who got either a mammogram or a breast MRI and tracked the care and costs that followed. They found:

  • Three-fourths of women who had a breast MRI had a “potential cascade event,” including lab tests, imaging tests, procedures, visits, hospitalizations and new diagnoses).

  • Women who got a breast MRI had an additional 39 breast-related cascade events per 100 women and nearly 20 more non-breast health related events compared to women who got mammograms. 

  • Total spending on cascade events was higher for women who received breast MRIs by an average of $1,404.

The authors note that the claims data they used could not explain why someone got an MRI vs. a mammogram or why cascade events occurred, and it did not include women on Medicare, Medicaid or without insurance. They also make clear that they are not making value judgments — some of the cascade events could be helpful and appropriate care.

But these findings raise many important points for me. First, screening MRIs, unlike mammograms, are not automatically covered with no out-of-pocket cost for patients. So just getting the MRI could cost patients more even before any cascade events. Then there’s the stress and mental burden — imagine waiting weeks or months to have someone confirm whether or not you have cancer.

The authors are clear — a breast MRI may be the best option for women at higher risk for breast cancer. But these findings highlight the importance of matching the right screening option with the right patients.

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