SUMMARY: Breast cancer is the most common cancer among women in the United States and 1 in 8 women will develop invasive breast cancer during their lifetime. Screening mammography complemented by breast self exam and clinical breast exam has resulted in early detection of breast cancer and successful outcomes. Even though mammography is a sensitive screening test, a small percentage of breast cancers may not show up on mammograms but may be palpable on examination by the patient or the clinician. Further, mammograms are less likely to find breast tumors in younger women with dense breast tissue. A breast Magnetic Resonance Imaging (MRI) is more sensitive than mammography although the specificity of a breast MRI is lower, resulting in a higher rate of false-positive findings and potentially unnecessary biopsies. Microcalcifications in the breast can be missed by a breast MRI. Taking these factors into consideration, appropriate utilization of breast MRI becomes relevant.
The American Cancer Society (ACS) recommends an annual MRI as an adjunct to screening mammogram and clinical breast exam in certain groups with increased risk of breast cancer (See Figures). The authors conducted this study to determine the utilization of breast (MRI) in community settings. In this retrospective study, the authors reviewed data on 10,518 women from a not-for-profit health plan, and these women had at least one breast MRI between January 2000 and December 2011. The appropriateness of a breast MRI was determined using a prediction model obtained from electronic medical records on a subset of patients. Between 2000 and 2009, there was a 20-fold increase in the use of breast MRI from 6.5 per 10,000 women in the year 2000 to 130.7 per 10,000 in 2009. This increase then declined and stabilized to 104.8 per 10,000 by 2011. With regards to indications for a breast MRI, 51.7% had a family history of breast cancer, 30.1% had a personal history of breast cancer and 3.5% of women had a documented genetic mutation. It is interesting to note that of those who received screening or surveillance breast MRI’s, only 21% fulfilled the American Cancer Society (ACS) criteria for a breast MRI. Conversely, fewer participants (48.4%), with documented deleterious genetic mutations, received breast MRI screening. The authors concluded that breast MRI was over utilized in those who did not fit the ACS criteria and was under utilized in those with documented genetic mutations. It is their opinion that routine breast MRI screening is not recommended for a new breast cancer diagnosis or for breast cancer surveillance and should only be considered for the group of individuals who have the most benefit. Breast MRI is performed preferably between days 7-15 of menstrual cycle for premenopausal women, using a dedicated breast coil, with the ability to perform a biopsy under MRI guidance by experienced radiologists, during the same visit. Stout NK, Nekhlyudov L, Li L, et al. JAMA Intern Med. 2014;174:114-121.
