August 22, 2013 | by Hiu Chung So
Although magnetic resonance imaging (MRI) of the breast is generally better than mammography at detecting cancerous lesions, there are downsides to this more sophisticated test.
The drawbacks include costs — a breast MRI costs 10 times more than a mammogram — and a higher likelihood of "false positive" diagnoses that can lead to unnecessary tests and treatments. Further, in a recent study of presurgical screening, researchers found that women who had a breast MRI are more likely to undergo invasive mastectomies, which come with their own complications.
The study, published online in Breast Cancer Research and Treatment earlier this week, looked at screening and treatment data from more than 72,000 women diagnosed with breast cancer from 2000 to 2009.
After evaluating the data, the researchers found that women 65 or older who underwent a breast MRI are 20 percent more likely to opt for a mastectomy rather than breast-conserving surgery. Further, among women who underwent mastectomy, those who had a breast MRI are three times more likely to have a bilateral mastectomy (i.e., the removal of both breasts) compared to those who did not have a breast MRI (12.5 percent compared to 4.1 percent, respectively.)
However, women who undergo breast MRI are also about three times more likely to have cancer detected in both breasts (9.7 percent versus 3.7 percent in the no MRI group.)
Providing outside commentary on MedPageToday, Laura Kruper, M.D., director of City of Hope's Rita Cooper Finkel and J. William Finkel Women’s Health Center, said these findings warrant further research but that the upward trend and connection of breast MRIs and bilateral mastectomies does not mean that the former leads to the latter.
The only way to find out would be to "survey the patients to determine whether the patient made the choice to undergo a mastectomy ... based on the MRI finding," Kruper said.
The researchers concurred and wrote that additional studies are needed to better establish guidelines that explain "the benefits and harms of MRI — and the accompanying change in surgical approach."