Improving Breast Cancer Screening with Abbreviated Breast MRI
Mammography is the most common method for breast cancer screening, but its ability to detect cancer in dense breasts is significantly lower than in breasts that are mostly fatty tissue. Considering that nearly half of all women age 40 and older who get mammograms have dense breasts, there’s a need for other screening methods that can detect breast cancer more effectively in these women.
It is widely established that breast MRI is the most sensitive test available for breast cancer screening. But MRI has been restricted to high-risk women for a variety of reasons, including exam length, cost, and potential for generating false positive results. To address these challenges, Christopher Comstock, MD, Attending Radiologist and Director of Breast Imaging Clinical Trials at Memorial Sloan Kettering Cancer Center in New York City, supports an abbreviated breast MRI study to screen women with dense breasts. The exam simultaneously reduces MRI image acquisition and interpretation times to reduce costs associated with MRI. “This is the first step in improving screening,” says Dr. Comstock. “The goal of a shortened MRI is to reduce the time, complexity and number of sequences in breast MRI to allow it to be used in more women with dense breast tissue.”
The Abbreviated MRI for Breast Study
In a study titled "Comparison of Abbreviated Breast MRI vs Digital Breast Tomosynthesis for Breast Cancer Detection Among Women With Dense Breasts Undergoing Screening", published in the February 2020 edition of JAMA, Dr. Comstock looked at the invasive breast cancer detection rate of abbreviated breast MRI compared with digital breast tomosynthesis (DBT), or 3D mammography, in women with dense breasts undergoing routine screening. “The goal of this trial really was to break the mindset that MRI should be limited to just super high-risk patients, so we can expand and use this sensitive tool in a much broader range,” he says.
The abbreviated breast MRI scan detected significantly more invasive cancers than Digital Breast Tomosynthesis (DBT) or 3D Mammography. Of the nearly 1,500 women studied, 23 cases of cancer were diagnosed, of which abbreviated MRI found 22. The DBT exam diagnosed only 9 cases. “That’s a two-and-a-half-fold increase in sensitivity, and I think it's a strong indication that we're finding biologically significant cancers with abbreviated breast MRI. It's a good indication that these would relate to an improvement in outcomes because those types of cancers aren't going to go away on their own,” Dr. Comstock says.
Screening Breast MRI Protocol
The abbreviated Breast MRI protocol consists of a single, pre and post contrast injection sequence and a T2 weighted sequence that reduces a typical MRI breast exam from approximately 40 minutes to less than 10 minutes.
The exam requires gadolinium contrast to highlight vascular changes that can indicate cancer, while mammography and ultrasound focus on structural changes. Despite recent concerns around repeat MRI contrasted studies, particularly in light of Gadolinium Deposition Disease (GDD), Dr. Comstock says the risks can be mitigated by using macrocyclic agents with lower risks of deposition.
Establishing a breast screening MRI program is straightforward for any site already conducting MRI exams. “The beauty of this abbreviated MRI is that it doesn't require any new equipment. It can be offered at all centers that are currently doing breast MRI, and reading the studies is very familiar to radiologists. It just requires that they reduce the sequences,” says Dr. Comstock. Although reimbursement is limited because no procedure code is currently associated with the exam, Dr. Comstock believes his study is the first step toward raising awareness of this imaging option, leading to support from insurance companies and its adoption by radiology centers. Ultimately, he believes the abbreviated breast MRI exam could help thousands of women with dense breasts get the most efficient and effective screening exam. “Under diagnosis is still a big issue because over 40,000 women each year die of breast cancer,” Dr. Comstock says. “We want to try to improve finding cancer early, when it's more treatable, and hopefully reduce mortality. The abbreviated Breast MRI scan adds to our tools.”