Breast MRIs up, but focus on high-risk patients needed, researchers say

Testing and screening for breast cancer with magnetic resonance imaging is on the rise in community settings, but researchers say more work needs to be done to ensure that the more costly screening method is used by the high-risk patients who benefit the most.

Two studies, each published Monday in JAMA Internal Medicine, found that utilization of breast MRI is increasing, including among women who are at high risk of developing breast cancer. However, the growth is also happening among women who don't meet the criteria for appropriate use.

“We could do better at targeting the women who would benefit,” said Natasha Stout, assistant professor of population medicine at Harvard Medical School in Boston and an author of the study looking at trends in breast MRI use.

The study looked at female patients enrolled in a not-for-profit health plan and multispecialty group medical practice in New England. MRI utilization for all indications—screenings, diagnostic work-up, staging or treatment, or surveillance—grew from 2000 to 2009. Utilization stabilized in 2010 and dropped in 2011.

MRI is more sensitive than mammography in the detection of breast cancer, but it's also more expensive, requires an intravenous injection of contrast material, and has a higher number of false positives. A mammogram can cost between $80 and $140, depending if it is film or digital, while a bilateral MRI costs more than $600, Stout said.

“Most expert groups have recommended limiting its use to patients at substantially increased risk of breast cancer, such as women who have deleterious genetic mutations or strong family histories of breast cancer, or for selected clinical situations,” wrote the authors of the trends study.

In 2007, the American Cancer Society recommended routine use of breast MRI as an adjunct screening tool in these patients.

About half of the 372 women with documented genetic mutations were screened with MRI. Twenty percent of the women who received a breast MRI met the ACS' criteria.

“Our data suggest that the majority of women who underwent screening breast MRI did not meet the recommended criteria for appropriate use, whereas many who did meet the criteria did not undergo screening breast MRI,” they concluded.

The second study found that the use of breast MRI rose from 2005 to 2009, especially for diagnostic evaluations and screenings. These authors found that women at higher risk of breast cancer were more likely to be screened with breast MRI, which is aligned with the ACS' recommendations—but so were younger, white women and women who had a prior breast biopsy.

“We also identified a need for more appropriate risk-based use of breast MRI as a screening examination because we identified women at average risk receiving MRI screening and women at high risk not receiving MRI screening,” they said.

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