Sara Shaylor MD, Presenter: Nothing to Disclose

Carol H. Lee MD, Abstract Co-Author: Nothing to Disclose

Sandra Brennan MBBCh, MSc, Abstract Co-Author: Nothing to Disclose

Elizabeth A. Morris MD, Abstract Co-Author: Nothing to Disclose

Laura Liberman MD, Abstract Co-Author: Nothing to Disclose

D. David Dershaw MD, Abstract Co-Author: Nothing to Disclose

To determine the frequency of and reasons for recommending repeat biopsy after MRI guided 9-gauge vacuum-assisted biopsy, and to determine the how often cancer is diagnosed at surgery in these lesions

In this retrospective IRB-approved, HIPAA-compliant study, the need for informed consent was waived. From January 2004 through December 2008, 867 MRI guided 9-gauge vacuum-assisted breast biopsies were performed at our facility . Medical records were reviewed to determine the frequency and reasons for recommending immediate repeat biopsy after a benign result. Pathology reports of the MRI biopsy and subsequent excision were reviewed to determine the frequency of cancer at surgery. Patients who had mastectomy rather than targeted excision were excluded as correlation with the actual site of the MRI biopsy was often not possible. Statistical analysis was performed with the Fisher Exact test and 95% Confidence Intervals (CI) were calculated using the Geigy Scientific Tables

Core histology was malignant in 145/867 (17%) and benign and concordant in 499/867 (57%). Immediate re-biopsy was recommended for 223 (26%; 95% CI, 23-29%) lesions. The reason for this recommendation was atypical ductal hyperplasia (ADH) or other atypia in 76 (34%), lobular neoplasia (LN) in 64 (29%), imaging-histologic discordance or possible inadequate sampling in 42 (19%), papillary lesion without atypia in 24 (11%), radial scar in 11 (5%), and unusual or mixed histology in 6 (3%). 177/223 (79%) lesions underwent surgical biopsy and outcome was benign in 70 (40%; 95% CI, 32-47%), high risk in 84 (47%; 95% CI, 40-55%), and malignant in 23, giving a cancer detection rate of 13% (95% CI, 8-19%). Malignancy was found at surgical excision in 12% (8/65) of ADH cases (95% CI, 5-23%), 17% (8/47) (95% CI, 8-31%) of those with LN, 19% (6/31)(95% CI, 7-37%) of the discordant cases, 5% (1/22) (95% CI, 0-23%) of the papillary lesions, and none (0%; 95% CI, 0-20%) of the radial scars or other histologies

 Re-biopsy after 9-gauge MRI-guided vacuum-assisted breast biopsy was recommended in 26% (range, 23-29%) of cases. The cancer detection rate for re-biopsied lesions was 13% (range, 8-19%), which is similar to rates reported for other image-guided breast biopsies done with 11- and 14-gauge devices

Lesions yielding high risk or discordant histology at MRI-guided vacuum-assisted biopsy warrant surgical excision.

Shaylor, S, Lee, C, Brennan, S, Morris, E, Liberman, L, Dershaw, D, Rebiopsy after MRI-guided 9-gauge Vacuum-assisted Breast Biopsy: Incidence, Indications, and Outcome.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9003944.html