Time-related changes in yield an harms of screening breast MRI

1508 Background: MRI has been accepted as a useful adjunct to screening mammography in high-risk women. Concerns remain over false positive findings, however, and little is known about harms and yield over time. Such information will help women decide about enhanced surveillance. Methods: Of 350 high risk patients offered MRI screening, 320 underwent 757 screens with a 1.5 Tesla magnet from 2008 to 2012 alternating (q 6 mo.) with digital mammography. Data collected included patient characteristics, mammographic density, estimated lifetime risk, and need for additional imaging and/or biopsy. Harms were defined as second look ultrasounds, US or MRI guided core biopsies, surgical biopsies or recommendation for short interval follow up. Estimates of harms over time were modeled by logistic regression. A significance level of 0.05 was used for all testing. Results: Compliance with MRI screening as recommended was 91% with the first MRI, and was not associated with age, race or level of risk. Harms were highest...