Abstract P3-02-11: Screening Magnetic Resonance Imaging (MRI) of the breast in women at increased lifetime risk for breast cancer: A retrospective single institution study

Background: Multiple factors are associated with an increased lifetime risk of breast cancer, including inheritance of an abnormal BRCA 1/2 gene, history of lobular carcinoma in situ (LCIS) or atypical hyperplasia, family history of breast cancer or previous chest wall radiation. In 2007, the American Cancer Society released updated guidelines for breast cancer screening based on risk stratification. These guidelines added annual MRI screening to mammography for women with greater than or equal to a 20–25% lifetime risk. Breast MRI screening trials have consistently demonstrated a higher sensitivity of MRI for malignancy compared with mammography, with an additional cancer yield from MRI of approximately 3%. The purpose of this study was to evaluate MRI screening outcomes in women with an increased risk for breast cancer evaluated in an established breast subspecialty clinic within the University of Wisconsin (UW) Hospital and Clinics. Methods: Patients (Pts) were included if they were seen by a UW breast center nurse practitioner, medical or surgical oncologist between 1/1/2007–3/1/2011 with a diagnosis code of: family history of breast or ovarian cancer, genetic susceptibility to malignant neoplasm or genetic carrier, Hodgkin's disease, LCIS, or atypical hyperplasia. Pts with a co-existing diagnosis of invasive breast cancer or ductal carcinoma in situ prior to initial encounter were excluded. Demographic information, breast cancer risk factors, estimated lifetime risk of breast cancer and screening recommendations were abstracted from the medical record. Results of subsequent breast imaging examinations (including breast MRI, diagnostic and screening mammography, and image-guided biopsies) were analyzed with the use of the mammography information system (PenRad™). Results: Of 276 women who met the inclusion criteria, 148 underwent at least 1 screening breast MRI. The majority of MRI screened pts were premenopausal (82%) and Caucasian (96.6%) with a mean age of 42.5 (range 20–68) at their initial encounter. Eighty five percent had a first degree relative with breast cancer and 72.3% of pts undergoing MRI screening had a documented lifetime risk of breast cancer of 20% or greater using a validated model. Within this MRI-screened cohort, 18.2% had a known genetic predisposition to breast cancer. Over the time assessed, 307 MRIs were performed in the 148 pts. Biopsy was recommended and performed based on the results of the MRI in 31 of 307 exams (10%). Ten cancers were detected for a positive predictive value based on biopsy performed of 32% and an overall cancer yield of 3.3% (10 of 307 MRI exams). All cancers were stage 0 - II. All pts are currently with no evidence of disease. Conclusion: Breast MRI has a high positive predictive value and cancer yield with an acceptable biopsy rate in a diverse group of high risk women undergoing breast MRI at an academic center outside of a clinical trial. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-02-11.