March 2, 2026 — A collaborative modeling study found that adding biennial breast magnetic resonance imaging (MRI) to routine mammogram screening could avert more breast cancer deaths among women with extremely dense breasts and higher-than-average cancer risk.
If MRI costs and false-positive biopsy recommendations are reduced, supplemental MRI directed to high-risk women with dense breasts could show promise. The study is published in Annals of Internal Medicine.
In response to new federally mandated breast density notification regulations, researchers funded by the National Cancer Institute aimed to determine when supplemental breast MRI is most beneficial for women receiving standard breast cancer screening.
They used Breast Cancer Surveillance Consortium (BCSC) data with three Cancer Intervention and Surveillance Modeling Network (CISNET) breast cancer simulation models to compare clinical and economic population-level outcomes of digital breast tomosynthesis (a 3D mammogram) alone versus a 3D mammogram combined with MRI for women ages 40 and over at average to 4 times higher breast cancer risk levels.
The results showed that mammography prevented the majority of breast cancer deaths, while adding MRI provided modest additional benefit and also led to more false-positive biopsy recommendations. When MRI was added for women with extremely dense breasts and at least double the average breast cancer risk, the balance of benefits and harms where comparable to mammography screening.
The researchers conclude that supplemental MRI could be a reasonable option for higher-risk women with dense breasts, especially if MRI costs and unnecessary biopsies can be reduced.
September 10, 2026 
