Sarah Stamler MD, Presenter: Nothing to Disclose

Janice S. Sung MD, Abstract Co-Author: Nothing to Disclose

Christopher E. Comstock MD, Abstract Co-Author: Advisory Board - Bayer

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

Kirti Magudia PhD, Abstract Co-Author: Nothing to Disclose

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

To compare the clinical, imaging and histopathologic features of MRI screen detected (SCA) and interval cancers (IC).

Retrospective review of 28,061 breast MRIs performed between 2005-2010 identified 120 SCA and 48 IC (cancer diagnosed within 364 days after a negative MRI). Medical records were reviewed for age at diagnosis, risk factors (family or personal history of breast cancer, BRCA status, prior high risk lesion), and tumor histopathology. For IC, the method and time interval from the negative MR were determined. Statistical analysis was performed using Prism software (GraphPad Software). The unpaired t and one-way ANOVA tests were performed to determine p-values.

Median age at diagnosis was 53 years for SCA and 50 years for IC. IC were not associated with any risk factor or tumor subtype (p>0.36). Mean size of invasive cancers was 0.8 cm for SCA and 0.7 cm for IC. SCA were highly associated with invasive cancers (SCA: 87/120, 73%, IC: 18/48 , 37%, p<0.0001), while IC were highly associated with DCIS (SCA:33/120, 27%, IC:30/48, 63%, p<0.0001). DCIS detected on screening MRI included 3 (9%) low grade, 17 (52%) intermediate, 12 (36%) high grade, and 1 (3%) unknown, compared to 7 (23%) low grade, 17 (57%) intermediate, and 6 (20%) high grade in IC (p=0.0264). Of the 48 IC, 8 (17%) were palpable, 34 detected on screening mammography (33 (67%) calcifications, 1 (2%) mass), and 6 (13%) on MRI. Median time to IC diagnosis was 185 days. Only 5 IC (1 IDC, 4 DCIS) were detected within 90 days of a negative MRI. In 9 women with BRCA-1 mutations, 8 had SCA (8 invasive cancers, 1 DCIS) and 1 IC (IDC) compared to 4 SCA (3 IDC, 1 DCIS) and 4 IC (1 IDC and 3 DCIS) in the 8 with BRCA-2 mutations.

Screening MRI preferentially detects invasive cancers and intermediate and high grade DCIS. Most IC after a negative MRI are detected as mammographic calcifications, representing low to intermediate grade DCIS. No clinical or histopathologic features are associated with the development of IC.

Tumor biology of MRI SCA differ from IC. Women undergoing breast cancer screening with mammography and MRI may benefit from alternating screening at 6 month intervals, regardless of BRCA status.

Stamler, S, Sung, J, Comstock, C, Dershaw, D, Magudia, K, Morris, E, Comparison of the Clinical, Imaging, and Histopathologic Features of Screen Detected vs Interval Cancers on Breast MRI.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045522.html