Hanan Ibrahim Khalil MD, Presenter: Nothing to Disclose

Ana P. Lourenco MD, Abstract Co-Author: Nothing to Disclose

Linda L. Donegan MD, Abstract Co-Author: Nothing to Disclose

Mary M. Hillstrom MD, Abstract Co-Author: Nothing to Disclose

Elizabeth Lazarus MD, Abstract Co-Author: Nothing to Disclose

Martha Beretta Mainiero MD, Abstract Co-Author: Nothing to Disclose

To determine the underestimation rate of high risk lesions diagnosed at MR-guided breast biopsy.

IRB approval was obtained for this HIPAA compatible retrospective review of 446 MR-guided breast biopsies performed from 2006 through 2010. Data were collected on indication for MR, size and type of lesion and biopsy results. Biopsies were performed with a 9-Gauge vacuum assisted biopsy device at 1.5T or 3T with a dedicated 7 or 16 channel breast coil. An average of 10 cores (range 6-13) was obtained. MR-biopsy results of atypical ductal hyperplasia (ADH), papillary lesion, radial scar, lobular neoplasia and atypia were identified and compared to final surgical pathology results. Data were analyzed for underestimation rate and for statistical significance in correlation with e with patient and lesion characteristics.

Of the 446 MR needle biopsies, 96 (21.5%) were high risk lesion. Mean lesion size was 1.6 cm (range 0.4-6), 42/96 (44%) were masses and 54/96 (56%) were non-mass enhancement. 45/96 (46.8%) were performed for preoperative staging, 41/96 (42.7%) screening and 10 (10.5%) for other reasons. 20/96 (20.8%) were ADH, 9/96 (9.5%) were lobular neoplasia, 27/96 (28.1%) were papillary lesions, 20/96 (20.8%) were radial scar and 20/96 were other atypias (20.8%). 69/96 (71.9%) had excisional surgical pathology available. Of these, 16/69 (23.2%) were upgraded to malignancy; 11/16 (68.7%) to DCIS and 5/16 (31.3%) to invasive carcinoma. Underestimation rate was 7/32 (21.8%) for masses and 9/37 (24.3%) for nonmass lesions; p=0.8. Underestimation rate was 9/33 (27.2%) for cases with known cancer and 7/36 (19.4%) without a known cancer; p=0.4. Underestimation rate was 6/28 (21.4%) for lesion size < 1 cm and 10/41 (24.4%) for ≥ 1cm; p=0.7. Underestimation rate for ADH was 6/19 (31.6%), papillary lesions 1/17 (5.9%), radial scar 3/13 (23%), lobular neoplasia 2/7 (28.6%) and other atypias 4/13 (30.7%); p=0.4.

The rate of high risk lesion at MR-guided biopsy was 21.5%. The underestimation rate was 23.2% for the cases with available excisional pathology. No patient or lesion factors correlated with underestimation rate.

Knowing the upgrade rate of high risk lesions diagnosed at MR biopsy is important for providing patient counseling regarding the need for surgical excision and likelihood of underlying malignancy.

Khalil, H, Lourenco, A, Donegan, L, Hillstrom, M, Lazarus, E, Mainiero, M, High-Risk Lesions at MR-guided Breast Biopsy: Frequency and Rate of Underestimation.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11009503.html