Breast cancer screening and surveillance MRI use increased significantly over a decade - but not among the women who need it most.
Breast MRIs for both screening and surveillance has stabilized after 10 years of sharply increased use. But many women who need the screening are not receiving it, according to a study published in JAMA Internal Medicine.
MRI for breast imaging is generally limited to high-risk women because of its low specificity, little evidence regarding mortality benefits, and its cost. However, since MRI use for breast screening and surveillance has increased, researchers in Boston undertook a retrospective cohort study to determine how they were used in the community setting.
Images were obtained from the files of 10,518 women, 20 years or older, who were part of a multispecialty group medical practice and who were enrolled in a not-for-profit-health plan. The women had had at least one breast MRI between January 1, 2000, and December 31, 2011. The researchers determined whether the imaging was performed for screening, diagnostic evaluation, staging or treatment, or surveillance.
The results showed that breast MRI use rose from 6.5 per 10,000 women in 2000 to 130.7 per 10,000 women in 2009 - a 20-fold increase. By 2011, fewer images were performed, declining to 104.8 per 10,000 women, where use stabilized.
In 2000, MRI screening and surveillance were rare, but by 2011, 57.6 percent of MRI breast imaging was for screening and surveillance. The researchers found that 30.1 percent of the women had a claims-documented personal history and 51.7 percent had a family history of breast cancer. However, only 3.5 percent of the patients had a documented genetic mutation.
“In the subset of women with electronic medical records who received screening or surveillance MRIs, only 21.0 percent had evidence of meeting American Cancer Society (ACS) criteria for breast MRI,” wrote the authors. “Conversely, only 48.4 percent of women with documented deleterious genetic mutations received breast MRI screening.”
The researchers concluded that although breast MRI use for both screening and surveillance increased steeply between 2000 and 2010, leveling off in 2011, the majority of patients did not meet ACS criteria for the imaging and many women who did meet the criteria, those with genetic mutations, were not screened.