Better Scan for High-risk Breast Cancer

Ivanhoe Newswire
Tuesday, July 10, 2007; 12:00 AM

(Ivanhoe Newswire) -- Women with a high risk of developing breast cancer have a better chance of catching their cancer in the earliest stages with magnetic resonance imaging (MRI). In a new study, MRI found tumors missed by mammography and ultrasound.

Researchers from six facilities, including the University of Washington School of Medicine in Seattle, compared how well the three screening methods found tumors in women at high risk for breast cancer.

Only about 5 percent to 10 percent of all breast cancers are caused by genetic predisposition, according to the National Cancer Institute. However, women in this high-risk group are more likely to develop cancer at a younger age than women of normal risk. Women younger than 50 typically have dense breast tissue, making spotting tumors difficult. The American Cancer Society recommends women with a high risk of breast cancer be screened with MRI plus a yearly mammogram beginning at age 30.

"Women at high risk for breast cancer can benefit from undergoing screening MRI," the study's lead author, Constance Dobbins Lehman, M.D., Ph.D., from the University of Washington School of Medicine, was quoted as saying. "Of all the breast imaging tools we have currently available, MRI is clearly the best at detecting cancer."

Researchers studied 171 women older than 25 who had not been diagnosed with breast cancer, but had been told they have at least a 20 percent lifetime risk of developing the disease. Researchers screened each of the women using MRI, mammography and ultrasound.

The screenings lead to 16 biopsies, which uncovered six cancers. MRI detected all six cancers, two were detected by mammography, and only one was found by ultrasound. Four of the cancers were found in women with dense breast tissue. Only MRI found those cancers.

Study authors report these findings lead them to believe MRI screening will find 23 more cancers for every 1,000 high-risk women screened. However, the authors caution MRI screening has not been proven as an effective way to detect cancer in women at average risk of developing breast cancer. MRI may lead to more biopsies than necessary in women at average risk.

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SOURCE: Radiology, 2007;244:381-388