Brian Nicholas Dontchos MD, Presenter: Nothing to Disclose

Habib Rahbar MD, Abstract Co-Author: Nothing to Disclose

Savannah Corrina Partridge PhD, Abstract Co-Author: Nothing to Disclose

Larissa Korde MD, MPH, Abstract Co-Author: Nothing to Disclose

Sue Peacock MSC, Abstract Co-Author: Nothing to Disclose

Constance D. Lehman MD, PhD, Abstract Co-Author: Consultant, Bayer AG Consultant, General Electric Company Research Grant, General Electric Company

Imaging assessments of amounts of fibroglandular tissue are known markers of breast cancer risk. Variable levels of enhancement of normal breast tissue on MRI (background parenchymal enhancement [BPE]) also may be predictive of breast cancer development. We explored whether BPE can further refine breast cancer risk assessments beyond mammographic density and amount of fibroglandular tissue on MRI in high risk women.

After IRB approval, we identified all high risk screening MRIs at our institution from 1/2006 to 12/2011 in women ≥18 years with no history of breast cancer. Outcomes were determined from our regional tumor registry. Women diagnosed with breast cancer any time after the index MRI comprised the cancer cohort. A 1:1 case control was created from a randomized cohort of women who did not develop breast cancer by last follow-up (minimum 3 years after index MRI), matching for age and BRCA mutation, and maximizing follow-up time. BPE, amount of fibroglandular tissue on MRI, and mammographic density were assessed on index exams and compared between the cancer cohort and negative controls using conditional logistic regression analyses.

From 5333 exams during the study interval, 23 high risk women (6 BRCA mutations) with no history of breast cancer underwent screening MRI and were subsequently diagnosed with breast cancer during the follow up interval (12 invasive, 11 in situ). Cancer cohort mean age was 47 ±10 years. Mean time-to-diagnosis of cancer was 779 ± 600 days, and mean follow-up time for negative controls was 2037 ± 458 days. Women with mild, moderate, or marked BPE on their index MRI had an approximately 9 times greater risk of cancer diagnosis during the follow-up interval than those with minimal BPE (OR=9.0, CI: 1.1-71.0). Neither amount of fibroglandular tissue on MRI nor mammographic density was a significant predictor of cancer risk (OR=1.2, CI: 0.4-3.9; OR=1.4, CI: 0.4-4.4, respectively).

Increased BPE may be associated with a higher probability of developing breast cancer in high risk women. Amounts of fibroglandular tissue measured by mammography or MRI may be less predictive of future breast cancer diagnosis in the high risk population.

Increasing background parenchymal enhancement on MRI correlated with future breast cancer development among high risk women and could be used as a predictive biomarker of breast cancer risk.

Dontchos, B, Rahbar, H, Partridge, S, Korde, L, Peacock, S, Lehman, C, Imaging Biomarkers of Breast Cancer Risk: Does MRI Background Parenchymal Enhancement Increase the Likelihood of Breast Cancer in High Risk Women?.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14001769.html