MRI can detect breast disease missed by mammography

Researchers have found that mammography coupled with magnetic resonance imaging (MRI) is extremely sensitive in the detection of ductal carcinoma in situ (DCIS). DCIS, or early stage breast carcinoma, is a pre-invasive malignancy and MRI may help identify this type of disease, which may not be visible on a mammogram. This study is published in The Breast Journal.

The study examined the medical records of women diagnosed with DCIS, aged 34 to 79 years, who underwent MRI and mammographic examinations during a period of approximately two years. The results revealed 39 sites of pure DCIS in 33 breasts of 32 women. In each of these women, both MRI and mammograms were performed prior to surgery. Of the 33 breasts involved, DCIS was detected by MRI alone in 64 percent, and detected by mammography alone in only 3 percent. MRI and mammography together detected DCIS in 24 percent of breasts; in 9%, DCIS was found at mastectomy but the mammogram and MRI were negative.

“The results from our small, select group of patients suggest that in women with known or suspected DCIS, determination of the presence and extent of disease may be best established with mammography complemented by MRI,” say researchers.

The nuclear grade of DCIS detected by MRI and mammography was similar, though the size of lesions identified by MRI was larger. Breast density did not affect the results.

The American Cancer Society recommends that women age 40 and older should have a mammogram every year and that those at increased risk should talk with their doctors about the benefits and limitations of starting mammograms when they are younger, having additional tests (such as MRI) or having more frequent exams.