Breast cancer is the second leading cause of cancer deaths for women in the United States . Despite recent controversy over screening regimens , several meta-analyses of randomized controlled trials demonstrate that mammography reduces mortality [3–5]. Presumably, screening reduces mortality by finding potentially fatal cancers early enough so that treatment is successful. In 2003, a total of 51,479,694 women (68% of the 73,858,958 women in the United States) reported using mammography in the past two years .
The sensitivity of digital mammography is about 70% . Contrast enhanced magnetic resonance imaging (MRI) of the breast has a sensitivity of 88.1% . In 2007, the American Cancer Society (ACS) issued guidelines suggesting that women at elevated risk for breast cancer be screened with breast MRI as an adjunct to mammography . The ACS recommended screening with breast MRI and mammography in women 1) who have a BRCA1/2 mutation, or are the untested first degree relative of a BRCA1/2 mutation carrier; 2) who have a lifetime risk of breast cancer of 20% to 25% or greater, as defined by a risk model that takes into account extended family history; 3) who are at elevated risk because of an inherited cancer syndrome; or 4) who have had previous radiation therapy to the chest between 10 and 30 years of age.
In this study, we collected the de-identified screening records of all 64,659 women presenting for breast cancer screening between January 2008 and January 2009 at Invision Sally Jobe Breast Centers, a private practice in the Denver metropolitan area. As the standard of care at Invision Sally Jobe, every woman presenting for screening mammography underwent risk assessment. If the women had 20% or higher lifetime risk of breast cancer, the radiologist reading the screening exam included in the mammography report a recommendation to the primary care physician that the woman receive breast MRI screening.
The results presented in this paper are from an observational study of a clinical implementation of the ACS recommendations at a single center, in single city. Thus, results may not be generalizable to other clinics. The risk assessment method and the process for recommending breast MRI screening in this study may not be the optimal way to implement the ACS recommendations. However, this is the first published report of any implementation of the ACS guidelines for breast MRI screening.
The purpose of this study is to estimate the proportion of women presenting for screening mammography who have a 20% or greater lifetime risk of breast cancer as determined by the Gail model [10,11]. As a second, exploratory aim designed to provide preliminary information for a proposed follow-up study, we report on the proportion of women who completed the recommended MRI at the same clinic which had conducted the risk assessment.