ACS Recommendations on MRI and Mammography for Breast Cancer Screening

Women at high risk of developing breast cancer should receive annual magnetic resonance imaging (MRI) as an adjunct to mammography, according to new guidelines from the American Cancer Society (ACS).

Groups for whom MRI screening is recommended include the following:

• Women with a first-degree relative who has a BRCA mutation

• Women with a BRCA mutation

• Women with a 20 to 25 percent or greater lifetime risk for breast cancer, based on BRCAPRO or other risk models that depend largely on family history

• Women exposed to chest radiation between the ages of 10 and 30 years

• Women with Li-Fraumeni syndrome, and first-degree relatives of women with this syndrome

• Women with Cowden and Bannayan-Riley-Ruvalcaba syndromes, and first-degree relatives of women with these syndromes

MRI screening has been proven to detect cancer with early-stage tumors, which are associated with better outcomes. Studies have found high sensitivity for MRI, ranging from 71 to 100 percent versus 16 to 40 percent for mammography alone in high-risk populations. MRI also finds smaller tumors compared with mammography, and the types of cancers found with MRI contribute to reduced mortality rates.

Three approaches are available for identifying women with a high risk for breast cancer: family history, genetic testing, and clinical history. Although many women have at least one relative with breast cancer, most of these women are not at increased risk. Only 1 to 2 percent of women have a family history suggestive of the inheritance of an autosomal-dominant, high-penetrance gene that confers up to an 80 percent lifetime risk of breast cancer. In some families, there is also a high risk of ovarian cancer. Family history findings that suggest the presence of such a high-penetrance gene include two or more close relatives (i.e., first- or second-degree) with breast or ovarian cancer; breast cancer occurring before 50 years of age in a close relative; a family history of breast and ovarian cancers; one or more relatives with two cancers (breast and ovarian cancers or two independent breast cancers); and male relatives with breast cancer.

Inherited mutations in the two breast and ovarian cancer susceptibility genes, BRCA1 and BRCA2, are present in approximately one half of families in which an inherited risk is strongly suspected. Several models can help physicians determine risk estimates: the Gail, Claus, and Tyrer-Cuzick models are based on family history, and BRCAPRO and the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) estimate the likelihood of BRCA mutations.

Genetic testing for BRCA mutations usually is offered to adult members of families with a known mutation and to women with a 10 percent or greater likelihood of carrying such a mutation. If a woman from a family in which a BRCA mutation has been identified does not have that mutation, her breast cancer risk is no higher than it would have been if she did not have a family history of breast cancer. However, in women from high-risk families without a known mutation, failure to find a mutation does not reduce risk.