MRI Detects Early Breast Cancer Cells
Study Shows MRI Screening Has High Detection Rate of Precancerous Cells
WebMD News Archive
The Problems With MRI continued...
But false positive results remain the biggest impediment to the use of
breast MRI in the screening of average-risk women, Saslow says.
The imaging technique is so sensitive that it finds many suspicious growths
that turn out not to be breast cancer (false positive), resulting in many
In the roughly 2% of American women who are considered to be at high risk
for breast cancer, the benefits of screening MRI outweigh these risks, but
Saslow says this is not true for most other women.
"For average-risk women, the harms of MRI outweigh the risks," she
says. "In addition, there have been no studies, including the current one,
which assessed MRI screening of women who were not at high risk."
Roughly one in six (29 of 167) of detected DCIS cases in the study by Kuhl
and colleagues occurred among average-risk women. The rest, Saslow points out,
occurred in women with a known elevated breast cancer risk.
Ninety-three were referred for MRI because of abnormal mammograms, 18 had
been treated for breast cancer, and eight had family history of the
"The women in the study were not representative of the population at
large, so it doesn't tell us much about the use of MRI in average-risk
women," she says.
The Promise of MRI
About 20% of breast cancers now detected are confined to the milk ducts,
compared to just 2% prior to the widespread use of mammography.
In an editorial accompanying the German study, radiology professor Carla
Boetes, MD, PhD, of Radboud University in The Netherlands, writes that while
mammography had dramatically improved the detection of these very early breast
cancers, wider use of screening MRI might have an even greater impact.
"That only 20% of tumors detected through screening are pure DCIS is
disappointing, when one keeps in mind that most breast tumors probably evolve
from DCIS," she writes. "The observation that MRI detects many DCIS
lesions that go unnoticed on mammography implies that some invasive carcinomas
can be prevented by timely intervention on the basis of MRI findings."