According to a study presented at the San Antonio Breast Cancer Symposium, magnetic resonance imaging (MRI) coupled with mammography detects almost all cancers at an early stage, reducing the incidence of advanced breast cancer in high-risk women.
The study, " A Prospective Study of Breast Cancer Incidence and Stage Distribution in Women with a BRCA1 or BRCA2 Mutation under Surveillance with and without Magnetic Resonance Imaging," was presented during a general session on Thursday, December 10.
Researchers separated 1,275 women at high risk for breast cancer into two groups. One group was screened with MRI and mammography, while the second, a control group, received conventional screening by mammography. All participants had the defective BRCA1 or BRCA2 gene mutation, which suggests a very high lifetime risk of developing breast cancer.
Lead researcher Ellen Warner, MD, MSc, medical oncologist in the Department of Medicine, Division of Medical Oncology at Sunnybrook Health Sciences Center in Toronto, Canada, and colleagues followed the women over several years to determine which screening method detected cancer at a significantly earlier stage. Forty-one cases of breast cancer were diagnosed in the MRI group compared with 76 diagnoses in the control group. Proportionately fewer advanced breast cancers and more early cancers were found among women who screened with MRI compared with those not screened with MRI.
Tumor size was also smaller in the MRI group. The average size of invasive cancers in the MRI group was 0.9 cm compared to 1.8 cm in the control group. Three percent of cancers in the MRI group were larger than 2 cm in diameter compared with 29 percent of those in the control group.
"These results will hopefully convince high-risk women and their healthcare providers that breast screening with yearly MRI and mammography is a reasonable alternative to surgical removal of their breasts, which is commonly done to prevent breast cancer," said Dr. Warner.