While MRI screening has been routinely recommended to women with a high breast cancer risk, the utility of screening additional women is unknown. Researchers from the University of Bonn and Aachen University in Germany MRI studies of over two thousand women, finding supplemental MRI detects more cancers than supplemental ultrasound.
MRI found an additional 15.5 cancers per 1000 cases, and the positive predictive value of 25 to 40 percent was substantially higher than ultrasound’s 8.4 to 11.7 percent. MRI screening also brought other benefits, according to the authors.
“After a negative MRI screening study, on average, the first screening diagnosis of breast cancer was not made until almost three years later,” they wrote. “This suggests that the protective shadow of MRI screening, in other words, a screening interval that results in low risk of an interval cancer in most women, may last longer than values observed for mammographic screening. If confirmed in future trials, this may imply that MRI screening may permit longer screening intervals to maintain a low rate of interval cancers.”
The next step for supplemental MRI breast screening is an economic analysis with particular attention paid to any reductions in recall rates. Lowering recall rates is a primary driver of savings when optimizing a cancer screening program, which can involve high-cost imaging, according to the authors.
“Although the direct costs associated with MR imaging vary widely between countries, it is clearly one of the most cost-intensive medical imaging methods,” the authors wrote. “Future cost-benefit analyses must consider the low interval cancer rate of screening MR imaging, as well as the possible downstream savings secondary to earlier diagnosis of biologically aggressive cancers.”
The authors acknowledged limitations stemming from the use of specialized breast radiologists: general radiologists may have poorer detection rates until they gain experience reading breast MR screening exams. Additionally, the cost-effectiveness of the program may be the most important piece of data, something that wasn’t looked at during this study.
Nevertheless, the authors are confident in the usefulness of MRI screening for average risk women, writing “MRI screening improves early diagnosis of biologically relevant breast cancer in women with average risk of breast cancer and was associated with an interval cancer rate of zero.”