Breast MR in community practices meets ACR benchmarks

A study of over 13,000 MR breast screening exams determined the modality was meeting performance benchmarks set by the American College of Radiology, but found room for improvement on false-positive results, according to an article published online in Radiology.

The use of magnetic resonance imaging (MRI) for breast screening first gained popularity in the early 2000s, with utilization steadily increasing until around 2012 before it leveled off. The American College of Radiology (ACR) provides a standardized reporting and performance benchmarks through the Breast Imaging Reporting and Data system (BI-RADS) and the Breast Cancer Surveillance Consortium (BCBS).

With 11.5 women of 1,000 receiving breast MRI every year, a multi-institutional group of researchers wanted to take its temperature and compare real-world performance to current BI-RADS benchmarks.

Led by Janie M. Lee, MD, associate professor of radiology at the University of Washington, the study authors compiled breast MRI exams from six sites participating in the BCBS.

After excluding some women based on previous cancer diagnoses, Lee et al. found the cancer detection rate in the study cohort approached the benchmark set by the ACR, at 17 detections per 1,000 examinations—the standard is 20 to 30 cancers detected. Additionally, the studied exams cleared the threshold for positive predictive value and got very close for specificity. This trend of “close but no cigar” signals room for improvement, according to the authors.

“The PPVs, along with MR imaging specificity, which approached but did not meet the benchmark of 85 to 90 percent, suggest that a continued focus on reducing false-positive results while maintaining sensitivity and cancer detection remains important for ongoing quality improvement efforts at population, facility, and individual radiologist levels.”

However, breast MRI screening was successful in catching cancer early.

“Further examination of breast cancer characteristics indicated that both screening-detected and interval cancers had favorable prognostic characteristics,” the authors wrote. “The proportion of cancers that were larger than 20 mm or node positive was comparable across the two groups. This suggests that screening MR imaging is effective in detecting most breast cancers within the detectable preclinical phase.”

The study also found there were disparities in access to MRI screening among high-risk women. Lower educated women are 60 percent less likely to go under the magnet, while college-educated women were 2.5 times more likely, representing an opportunity to improve risk communication among care providers and patients.

According to the authors, the most important takeaway from this study is the validation of breast MR screening in a community setting: real-world clinical performance can meet or approach benchmarks based on expert performance in clinical trials. Individual practices can compare their performance with BSBC performance or BI-RADS benchmarks to learn about their personal performance and to highlight areas for improvement.