MRI Beats Mammography in Detecting Breast Cancers
Mammography does not improve breast cancer detection in high-risk women already undergoing screening with MRIs.
In 2007, the American Cancer Society published guidelines to include MRIs in addition to mammography to screen women at high risk of breast cancer. But are both approaches necessary in this population?
To evaluate the value of mammography in detecting breast cancer in high-risk women also undergoing MRI screening, researchers analyzed the outcomes of nearly 4,000 screening studies in 1,249 high-risk women. The results were published this month in the journal Radiology.
The results bring into question the usefulness of mammography in high-risk women already undergoing annual MRI screening. A total of 45 breast cancers were diagnosed: 43 were detected with MRI and 14 with both mammography and MRI. Importantly, no cancers were found with mammography that were not also detected with MRI.
The cancer detection rate for MRI was 21.8 cancers per 1000 examinations, compared to 7.2 cancers per 1000 examinations for mammography. Mammography was inferior to MRI in sensitivity (31 percent versus 95.6 percent) but had better specificity (89.4 percent versus 78.4 percent) and false positive rate (10.4 percent versus 21.1 percent).
Currently, breast MRI is not recommended as a stand-alone screening test, but as a supplement to mammography. This study suggests that screening mammography does not improve cancer detection in women who also undergo MRI screening. Since mammography is associated with high costs and radiation exposure, the researchers conclude that routine use of mammography in women undergoing breast MRI warrants reconsideration. They suggest using MRI as a stand-alone screening test and cutting back the use of mammography in high-risk women.