Two Studies Suggest Pattern of Misuse for Breast MRIs

Two large cohort studies, originally undertaken to gather data on national patterns of breast MRI use in community practice, suggest that the costly scan is being overused in women who won’t benefit from it and underused in women who could gain benefit from it. The studies involved different populations and different methodologies, yet found similar results.

The overall use of breast MRI has increased, with the procedure most commonly used for diagnostic evaluations and screenings, according to the studies published in the November 18 issue of JAMA Internal Medicine. Although its use is increasing, the test’s sensitivity leads to a higher false-positive rate.

Guidelines from the American Cancer Society indicate that breast MRI should be used to screen asymptomatic women at high risk for breast cancer, including known carriers of the BRCA gene mutation, first-degree relatives of a known BRCA gene mutation carrier who are themselves untested, or women with a greater than 20% lifetime risk of breast cancer.

Study authors Karen J. Wernli, PhD, Group Health Research Institute, Seattle, WA, and colleagues explained, "Understanding who is receiving breast MRI and the downstream consequences of this use should be a high research priority to ensure that the limited healthcare funds available are used to wisely maximize population health."

In the first study, researchers examined the patterns of breast MRI in US community practices from 2005 through 2009 with data collected from five national Breast Cancer Surveillance Consortium registries. They found that the overall rate of breast MRI nearly tripled from 2005 through 2009, with diagnostic evaluation (40.3%) and screening (31.7%) being the most common reason for ordering a scan. The proportion of women screened who were at high risk for breast cancer also increased during that period, from 9% to 29%.

The second study looked at 10,518 women (ages 20 and older) who were enrolled in a health plan for at least one year and had at least one breast MRI at a multispecialty group medical practice. Breast MRI counts, breast cancer risk status, and the reason for testing (screening, diagnostic evaluation, staging or treatment, or surveillance) were obtained.

According to the study results, use of breast MRI increased from 6.5 examinations per 10,000 women in 2000 to 130.7 exams per 10,000 women in 2009. The greatest increase was in breast MRI use for screening and surveillance. By 2011, breast MRI use had declined then stabilized (104.8 exams per 10,000 women). Breast screening and surveillance accounted for 57.6% of MRI use by 2011. Of the women, 30.1% had a claims-document personal history, 51.7% had a family history of breast cancer, and 3.5% of women had a documented genetic mutation.

Source:

• Wernli KJ, DeMartini WB, Ichikawa L, Lehman CD, Onega T, Kerlikowske K, et al. Patterns of breast magnetic resonance imaging use in community practice. JAMA Int Med. Online First. Nov 18, 2013 http://archinte.jamanetwork.com/article.aspx?articleid=1779731
• Stout NK, Nekhlyudov L, Li L, Malin ES, Ross-Degnan D, Buist DSM, et al. Rapid increase in breast magnetic resonance imaging use. Trends from 2000 to 2011. JAMA Int Med. Online First. Nov 18, 2013 http://archinte.jamanetwork.com/article.aspx?articleid=1779730