Breast Cancers Show “Surprising Characteristics” on MRI

MRI can effectively detect cancers missed by mammography and physical examination, but cancers can have some surprising characteristics on the MR image, a new study shows.

The study included 59 women with 65 cancers that were not detected by physical examination or on a mammogram, said Lia Bartella, MD, assistant professor of radiology at Memorial Sloan-Kettering Cancer Center in New York. The classic criteria for cancer on an MR image is a mass that looks bright after contrast media is injected into the breast, but it quite quickly loses its brightness, said Dr. Bartella. “In 63% of these patients, this didn’t happen,” she said. The mass took up the contrast, but there was no quick washout,” she said. One lesion showed progressive kinetics, which means that it got brighter and brighter on the MR image. This often happens when the lesion is benign, Dr. Bartella said. In addition, Dr. Bartella noted that in 62% of the cases, the cancer did not look like a mass.

Most of the cancers (70%) were stage 1 disease; 28% were stage 2, and 2% of the women had distant metastases, indicating that MRI can detect breast cancer at an early stage, said Dr. Bartella. Most of the women (68%) had a mastectomy, Dr. Bartella said. It is important to note that these women chose mastectomy; MRI offered most of them the chance to have breast-conserving treatment because their disease was caught early, she said.

These women were sent for an MRI examination for several reasons –13 of the women were at high risk of breast cancer; 41 of the women had known breast cancer, and the MRI was done to determine the extent of disease; and five of the women had an MRI after a problem was detected, but physicians were unsure of the diagnosis, said Dr. Bartella.

Dr Bartella will present the study on May 6 at the American Roentgen Ray Society Annual Meeting in Miami Beach, FL.