MRI Screening of Women at High Risk for Breast Cancer

In 2007, the American Cancer Society (ACS) published guidelines recommending women at “high risk” for breast cancer to receive annual screening using breast magnetic resonance imaging (BMRI) as an adjunct to mammography. We aim to calculate the lifetime risk of breast cancer among non-elderly women in California and estimate the likelihood of BMRI screening among “high risk” women by using mammogram rates and controlling for predisposing, enabling, and need characteristics.

We compared the general population and the “high risk” population by their characteristics and used logistic regression models to predict the odds of receiving a mammogram (BMRI) in the past year among those women categorized as “high risk”. All high risk women who received a mammogram were assumed to receive a BMRI.

We used data from the 2005 California Health Interview Survey (CHIS) and the Gail model to calculate the lifetime risk of breast cancer among women age 30-64 (n=14,312). Women with a lifetime risk of 20% or greater were classified as “high risk.” This definition of “high risk” did not include women with BRCA1 and BRCA2 genes or those exposed to Hodgkin's disease since the Gail model did not include those risk factors.

The percentage of women ages 30-64 without a prior history of breast cancer who were classified as high risk ranged from 0.9% to 1.2% depending on the assumptions made in the model. Approximately 74% of the women in the “high risk” group received a mammogram in the past year. The significant factors predicting annual mammograms (BMRI) in the past year among the high risk group were older age, being employed, having at least one doctor visit in the past year, and having more chronic conditions. Of the approximately eight million women aged 30-64 with no prior history of breast cancer, 14% were uninsured, 65% were in health insurance plans that would not cover breast MRI screening of “high risk” women, and 21% were in health insurance plans that would cover breast MRI screening of “high risk” women. If health insurers were to adopt the 2007 ACS guidelines, nearly 34,000 more BMRIs may be conducted in California annually.

The average cost of a BMRI is estimated at $1,300, leading to a significant rise in overall health care expenditures. Given the high rates of false positive BMRI results and its clinical and emotional consequences, broad implementation of this guideline and its public health impact should be carefully examined.