Researchers have developed a 7-minute MRI-based breast cancer screening protocol that will allow women with dense breast tissue to receive regular scans.
Regular mammograms are critical for the early detection of breast cancer, particularly in women who are at high risk. Dense overlapping breast tissue, compared to fatty breast tissue, can occlude lesions (tissue damaged by injury or disease) or be mischaracterized with mammography. Dense breast tissue makes mammographic imaging a challenge and women with this type of tissue are alternatively screened using magnetic resonance imaging, or MRI.
MRI is a costly alternative to mammography due to the cost of equipment and is still being optimized as an effective screening tool for breast cancer. Furthermore, the required injection of a contrast agent, reported high rates of false positives, and lack of expertise in interpretation of image data make MRI as a tool to detect breast cancer a challenging one. In an attempt to overcome these barriers, a group of researchers based in Michigan have developed a rapid protocol for breast cancer MRI screening that maximizes the detection of lesions that are not typically seen with standard mammography.
Between 2009 and 2011, 671 asymptomatic women with an average age of 55 years that had a negative mammogram were screened for breast cancer using a 7-minute full diagnostic ‘Rapid Breast MRI’ protocol. MRI results were read and analyzed independently by trained radiologists and scored using standard screening criteria. All types of suspicious and non-suspicious lesions were analyzed using three criteria: 1) morphology, 2) signal response from each individual acquisition, and 3) lesion intensity relative to surrounding tissue.
Of the women screened, just over half (55%) had dense breast tissue. 45% of these women had one or more lesions not detected on their mammograms. In the other half of women with non-dense breasts that were composed mainly of fatty or scattered fibroglandular tissue, 23% had one or more lesions not detected on their mammograms. The number of lesions detected by MRI screening in both types of breast tissue was 435 in total.
Seventeen suspicious lesions in 16 women were biopsied, 7 of which were found to be malignant. Of these, 4 women were diagnosed with malignant carcinoma while the others were diagnosed with ductal carcinoma. For these cases, the pathology reports were in alignment with results of MRI findings. All of the women had dense breast tissue and only 17% of them had a family history of breast cancer. MRI screening did not identify any suspicious lesions in women with non-dense breast tissue.
This is the first clinical study examining a rapid, MRI-based breast cancer screening protocol in women with a negative routine mammogram. The Rapid Breast MRI screening protocol cuts diagnostic MRI scan time by 70%, which when adopted more widely, will significantly reduce costs to both patients and insurance companies. The study protocol was successful in identifying malignant and non-malignant lesions, and uses an easier method to evaluate MRI data that reduces false positives. The Rapid Breast MRI has the potential to detect cancer earlier in women with dense breasts and to get screened on a regular basis.
At present, the Rapid Breast MRI is not yet covered by insurance providers in the U.S., so patients must pay out-of-pocket.
Written By: Fiona Wong, PhD