Breast Cancer Risk Assessment in 64,659 Women at a Single High-Volume Mammography Clinic

Rationale and Objectives: In 2007, the American Cancer Society (ACS) recommended that women at elevated risk of breast cancer be screened with breast magnetic resonance imaging (MRI) as an adjunct to mammography. This study estimates the proportion of women presenting for screening mammography who are at elevated lifetime risk of breast cancer as determined by the Gail model. This study provides preliminary information for a proposed follow-up study, including the proportion of women who completed the recommended MRI at the same clinic that had conducted the risk assessment. Materials and Methods: This study is an observational prospective cohort of 64,659 women presenting for mammographic screening at a single high-volume clinic. If a woman reported a first-degree maternal relative with breast cancer and had at least 20% lifetime risk on the Gail model, the radiologist's report included a recommendation that the primary care physician refer the woman for breast MRI screening. Records were examined to determine if women completed the recommended MRI at the clinic within one year of the initial risk assessment. Results: Of 64,659 women, 1,246(1.9%) had a lifetime risk of breast cancer of 20% or greater, and 436(0.7 %) had a lifetime risk of breast cancer 25% or greater. Of the women at elevated risk, 173 (13.9%) completed the recommended breast MRI screening at the clinic within a year. Conclusion: The effectiveness of matching screening intensity to risk on cancer detection, biopsy rate, and cost should be evaluated by studying multiple clinics and multiple risk assessment tools.