"This is the first time a prospective study has been done that shows that MRI (using a contrast agent) can work in a real life community setting - the setting in which most breast cancer patients are diagnosed and treated," said Jonathan I. Wiener, MD, lead author of the study. The study included 65 patients who had "highly suspicious" findings on mammography or sonography and were believed to be candidates for breast conserving treatment. Nineteen of the patients did not have a suspicious lesion on MRI, and when these women were biopsied, it turned out they did not have cancer, said Dr. Wiener. Many of those patients could have avoided having a biopsy at all, he said.
In addition, MRI detected 23 additional cancers in the 44 patients that actually had a breast cancer (either in the same breast as the primary cancer and or in the opposite breast) that were not detected on mammography or sonography. Because of the additional information provided by MRI, and subseqently confirmed by pathological analysis of the biopsy specimens, it was recommended that eight women have a mastectomy rather than breast conservation treatment. "About 15% of breast cancer patients have a recurrence of their disease. We don't know precisely why cancer returns in previously thought to be adequately treated breast cancer patients. One of the reasons could be that many of the cancers may be missed initially with only a conventional work up with mammography and ultrasound. The addition of MRI will improve the accuracy of breast cancer diagnosis," Dr. Wiener said.
"Breast MRI using contrast agents has been around for about 15 years," said Dr. Wiener. "Breast MRI isn't widely used because there are concerns that it detects too many lesions that are not cancer, thereby causing too many women to undergo unnecessary biopsies. However we used a special computer program (computer assisted diagnosis), which helped us analyze the MRI images, looking at both morphology and kinetics. Morphology looks at the shape of the lesion, while kinetics looks at how quickly the contrast agent lights up the lesion then fades away. If the lesion is bright then washes out quickly, it usually indicates cancer," he said. "By analyzing MRI using these and other factors, as well as carefully reviewing the mammograms and sonograms, we were able to more accurately answer the vital questions: does the patient have breast cancer and how extensive is the disease?" said Dr. Wiener.
The study appears in the March 2005 issue of the American Journal of Roentgenology.