Breast MRI apprehends most dangerous offenders

MR imaging is going for the holy grail of ductal carcinoma in situ imaging-identification of malignant cells that are the most aggressive and have greatest potential to kill the patient.

High-resolution MRI is much more sensitive for DCIS than state-of-the art mammography, according to a large prospective study by Dr. Christiane Kuhl and colleagues at the University of Bonn in Germany. Results were presented at the American Society of Clinical Oncology meeting in June.

Of nearly 6000 patients, 137 had a diagnosis of DCIS with no invasive cancer. Most (79%) were referred for regular screening, and another 10% presented for high-risk screening.

Of 11 DCIS cases detected only with mammography, one was high grade and none were estrogen receptive negative or HER-2 positive. But of the 55 DCIS cases found only on MRI, 41 (78%) were high grade, 14 were estrogen receptive negative, and 17 were HER-2 positive.

Breast MRI utilization has been increasing since the American Cancer Society recommended routine use in screening of high-risk women earlier this year.

Compared with mammography, MRI is better at picking up breast cancers prior to calcifications and at showing tumor vascularization, said Dr. Richard Reitherman, medical director of breast imaging services at Orange Coast Memorial Medical Center in California.

"DCIS is born without calcifications. That is the natural history of the disease. If it decides not to calcify, you don't have a hope of seeing it with mammography," he said.

Breast MRI is useful as an adjunct to other imaging techniques for screening and for evaluating the extent of disease to ensure all of the cancer is removed during surgery. Quality is critical, however, and as more people use breast MRI, service has varied greatly, from good to terrible, Reitherman said.

"It's very similar to the introduction of mammography in the mid-80s. Prevalence became very high, and a lot of places provided poor service. There was a tremendous quality problem," he said.