10-minute MRI beats 3D mammography for screening dense breasts

A speedy, 10-minute MRI can better detect invasive cancers in women with dense breasts, compared to digital breast tomosynthesis, new findings revealed Tuesday.

In the cross-sectional study, more than 1,400 women received DBT and abbreviated breast MRI, with the latter detecting 11.8 cancers per 1,000 women, compared to 4.8 in that same number of individuals for digital tomosynthesis. If confirmed in larger groups, the expedited imaging approach could offer women a lower-cost screening option, while reducing radiation and improving cancer detection.   

Additionally, follow-up in these women revealed no missed or additional cancers, researchers reported, Feb. 25 in JAMA

“The results of this study demonstrate that abbreviated breast MRI improved breast cancer detection in women with dense breasts; the fact that no interval cancers were observed during follow-up further supports this conclusion,” said Christopher E. Comstock, MD, with Memorial Sloan Kettering Cancer Center, and colleagues.

To gather their results, the team randomized 1,444 women ages 40 to 75 to receive a 10-minute MRI and a DBT exam. Imaging was completed at 47 institutions in the U.S. and one in Germany across a nearly two-year study period. Each individual had an average risk of breast cancer and dense breasts, according to their most recent mammogram.

In total, screening rooted out 19 invasive tumors in 17 women. Abbreviated breast MRI detected cancer in all individuals, while DBT discovered the disease in seven. That placed MRI’s sensitivity for detecting invasive cancer or ductal carcinoma in situ at 95.7%, with a specificity of 86.7%. For comparison, DBT—known as 3D mammography—notched a 39.1% sensitivity and 97.4% specificity. The authors noted that positive predictive values were low when using both modalities.

Comstock and co-authors did point out that screening via a 10-minute MRI can result in additional benign biopsy findings, a six-month follow-up recommendation, or both. “On the other hand, DBT, but not abbreviated breast MRI, may require further imaging after initial screen-detected abnormalities,” they added.

In an accompanying editorial, Anna Tosteson, with Dartmouth College’s cancer center, argued that abbreviated MRI still has a lot left to prove, including that it is more practical and cost-effective in large populations of women with dense breasts, compared to conventional breast magnetic resonance imaging.

She noted that, as it stands, the 10-minute exam costs women hundreds of dollars in out-of-pocket expenses. And the abbreviated approach still requires a contrast-enhancing agent similar to full-protocol breast MRI, “and thus carries the same gadolinium-associated risks.”

“Despite increased attention to tailored breast cancer screening that considers women’s breast density and breast cancer risk, firm evidence regarding the best approaches to supplemental screening for women with dense breasts remains elusive and is much needed,” Tosteson wrote. “Given the large number of women with dense breasts and the lengthy time horizon required to fully understand the potential benefits of emerging breast cancer screening technologies, it is imperative that systems be designed to track long-term screening outcomes.”