Using breast MRI for short term followup of BI-RAD 3 lesions
When a patient has a breast lesion identified as “probably benign”, or category 3 on the Breast Imaging-Reporting and Data System (BI-RADS) scale, short-interval follow-up magnetic resonance imaging (MRI) is an appropriate method to identify early stage breast cancer and avoid unnecessary biopsies of benign breast lesions, according to a study from Massachusetts General Hospital in Boston. Research presented at a scientific session of the American Roentgen Ray Society’s (ARRS) annual meeting held May 5-10 in Honolulu, HI, represented analysis of nearly 7,000 MRI screening exams.
Breast MRI is the most sensitive modality to detect breast cancer for breast cancer screening and its utilization continues to increase. Because little is known about short-term follow-up of probably benign findings with less than 2% chance of malignancy with MRI follow-up, the researchers conducted a consecutive study to evaluate the frequency and cancer yield of BI-RADS 3 lesions in patients undergoing baseline versus non-baseline high-risk screening MRI exams.
Out of 6,672 MRI screening exams performed in 3,3214 patients between 2011 and 2015, 202 were assigned a BI-RADS 3 categorization. These included 8.3% of baseline exams and 2.1% of non-baseline exams.
Session presenter and radiologist Leslie Rae Lamb, MD, reported that baseline breast MRI identified two malignancies and non-baseline exams identified 11. Eight malignancies were characterized as foci, three as non-mass enhancement, and two as masses.
“This study clarifies that probably benign assessments can be as useful for MRI as they are for mammography,” said Dr. Lamb. “Most cancers diagnosed on follow-up of BI-RADS 3 lesions are early stage and most are diagnosed at or before the six-month followup. The results indicate that when employed sensibly, short-interval follow-up MRI is an appropriate technique to identify early stage breast cancer.”
In a press release, co-author Christine Edmonds, MD, said,“Many patients and providers question the utility of BI-RADS 3 in MRI, particularly as some insurers do not cover the costs of the short interval follow-up MRIs. This study clarifies that short interval follow-up MRI is a valuable method of identifying early stage breast cancer while avoiding unnecessary biopsies.”