Supplemental MRI for Women with Dense Breasts

Starting in September 2024, the U.S. Food and Drug Administration is requiring that mammogram results provided to patients include assessment of breast density. For women with dense breasts, the results must state, “other imaging tests in addition to a mammogram may help find cancers.” Appropriate follow-up of such notifications remains uncertain, with recent U.S. Preventive Services Task Force guidelines citing insufficient evidence to recommend for or against supplemental screening based on breast density (NEJM JW Gen Med Jun 1 2024 and JAMA 2024; 331:1918).

In this study, researchers used well-established models to simulate outcomes if magnetic resonance imaging (MRI) were added to digital breast tomosynthesis (DBT) based on breast density. They projected the following:

• Biennial DBT screening for middle-aged women (age range, 50–74) would result in 7.4 breast cancer deaths averted and 884 false-positive recalls per 1000 women during lifetime screening. Adding biennial MRI for women with extremely dense breasts would increase deaths averted by 0.1 and false-positive recalls by 35. Extending MRI to women with heterogeneously dense breasts would lead to an additional 0.5 deaths averted and 170 additional false-positive recalls.
• Starting the above-stated scenarios at age 40 rather than age 50 would lead to similar increases in deaths averted but larger increases in false-positive recalls.
• Annual screening would increase the number of deaths averted slightly but would more than double rates of false positives.