Underutilization of Supplemental Magnetic Resonance Imaging Screening Among Patients at High Breast Cancer Risk

Breast cancer is the most common noncutaneous malignancy among women in the United States. ¹ Based on population-based randomized control trials, mammography is the gold standard for screening due to demonstration of reduced mortality rate. ^{2 –9} However, the sensitivity of mammography is reduced in specific populations, such as in women with dense breasts despite high risk, ¹⁰ defined as an estimated lifetime risk of >20%. ¹¹ The combination of mammography and contrast-enhanced breast magnetic resonance imaging (MRI) has been shown to increase the cancer detection rate in high-risk women compared with mammography alone. ¹² Multiple national societies, including the American Cancer Society, National Comprehensive Cancer Network, and American College of Radiology/Society of Breast Imaging, recommend supplemental breast MRI for screening in high-risk women. ^11,13,14 Nevertheless, screening breast MRI is underutilized. ¹⁵

In this issue of Journal of Women's Health, Miles et al. performed a cross-sectional study of 422,406 women undergoing screening mammography at 86 facilities in 6 areas (New Hampshire, Vermont, North Carolina, Chicago, Western Washington, and San Francisco) participating in the Breast Cancer Surveillance Consortium (BCSC) in 2012. They assessed whether the presence of breast MRI at centers where women underwent mammography played a role in breast MRI utilization. ¹⁶ They collected information regarding individual women (age, race/ethnicity, education level, estimated median household income and travel time based on residential zip code, prior breast biopsy, and family history) and participating facilities (academic affiliation, for profit or not for profit, practice type, and urban or rural). The majority of women were between the ages of 50 and 74 years, were white, had an unknown education level, did not have a low median household income, had a travel time between 15 and 30 minutes, did not have a prior breast biopsy, and did not have a family history of breast cancer. Most facilities were not affiliated with an academic institution, were not for profit, were a full diagnostic radiology practice, and were urban.

A total of 30.2% (26/86) facilities offered on-site breast MRI, and 44.5% (188,069/422,406) mammograms were performed at facilities with on-site breast MRI. Among high-risk women, 43.9% (2,403/5,468) underwent screening mammography at a facility that offered on-site breast MRI, yet only 6.6% (158/2,403) underwent supplemental breast MRI within a 2-year window of their mammogram. This result is lower than that reported by Wernli et al., which found that the percentage of high-risk women screened with supplemental breast MRI increased from 9% in 2005 to 29% in 2009. ¹⁵ One possibility is that women underwent breast MRI at a facility not participating in BCSC and, therefore, were not represented by the available data. Regardless, the low percentage of high-risk women undergoing breast MRI in this study as well as in other studies suggests that factors including but not limited to availability of on-site breast MRI and potentially decreased travel burden influence breast MRI utilization. Other factors such as lack of health insurance and primary care and relative high cost of breast MRI certainly influence breast MRI utilization, which may be even lower than the 6.6% reported in this study, especially considering women not already undergoing screening mammography nor captured by this data set.

Ideally, the widespread use of electronic medical software for charting could help increase awareness of lifetime risk by incorporating preliminary breast cancer risk assessment models for use during routine primary care visits, with automatic generation of reminders for mammography screening in women of all risk levels and additional ordering options for high-risk clinic referral and supplemental breast MRI screening in women of high risk. Among women who do undergo screening mammography, commercially available mammography reporting software could also help by calculating lifetime risk based on intake questionnaire questions and by automatically generating letters regarding high-risk clinic and supplemental breast MRI screening to both patients and referring healthcare providers. ¹⁷ The latter is already practiced by some imaging facilities, and future study is required to evaluate the impact of this practice.