Magnetic resonance imaging (MRI) alternated with mammography at six-month intervals can detect breast cancers not identified by mammography alone, a research team from The University of Texas M. D. Anderson Cancer Center will report at the 31st at the CRTC-AACR San Antonio Breast Cancer Symposium.
MRI is known to be more sensitive in detecting breast cancers than mammography, with a 71 - 100 percent accuracy compared to a 16 - 40 percent accuracy for mammography. As a result, annual breast cancer screening for high-risk women now typically includes MRI along with mammography and a clinical breast exam.
"In the high-risk population, the recent standard of practice is to perform mammography and MRI every year," said Huong Le-Petross, M.D., assistant professor of diagnostic radiology at M. D. Anderson and the study's first author. "What we started to do at M. D. Anderson was to see if we could do mammography and then six months later do a breast MRI exam, followed six months later with a mammogram exam, and then six months after that with a breast MRI. That way the women would receive an imaging modality screening every six months."
In the pilot study, to be presented at a poster session on Dec. 13, the researchers performed a retrospective chart review of 334 women who had participated in a high-risk breast cancer-screening program at M. D. Anderson from Jan. 1997 to Dec. 2007. The women had undergone between one and four MRI screening cycles and were considered to be at high risk if they had hereditary breast and ovarian cancer syndrome, a personal history of breast cancer, a biopsy indicating atypia or lobular carcinoma in situ (LCIS), or a 20 percent or higher lifetime risk of developing breast cancer, as estimated by the Gail model.
In the all-M. D. Anderson study, 86 of the 334 high-risk women (26 percent) underwent this alternating approach. Among this group, 46 percent completed the first round of MRI screening, 28 percent completed the second round, 13 percent completed the third round, and 4 percent completed the fourth round. The other 248 women underwent prophylactic mastectomy or were started on chemoprevention agents. All study participants were given a clinical breast exam every six months. The median follow-up time was 2 years, with a range of one to four years).