Purpose: To compare the effectiveness of breast MRI to mammography for the annual screening of women at high risk for breast cancer

Methods: A Markov model was created to compare annual screening over 25 years with either breast MRI or mammography for a cohort of women at high risk for the development of breast cancer (Claus model lifetime risk ≥15%). Data from published studies provided probabilities for the model including the sensitivity and specificity of each screening strategy, the probabilities of presenting with node positive breast cancer given the screening modality, and the probabilities of death for individuals with node positive breast cancer, node negative breast cancer, and those without cancer. Utilities from the literature were applied to each health outcome in the model including a disutility for the temporary health state following breast biopsy for a false positive test result, and utilities for node positive breast cancer, node negative breast cancer, and for undergoing screening without findings of cancer. Univariate and probabilistic sensitivity analyses addressed uncertainty in all model parameters. Ranges and distributions for probabilities and utilities were obtained from the literature and by the Doubilet method for constructing confidence intervals using normal approximations to the binomial distribution.

Results: Breast MRI screening provided 0.047 additional quality-adjusted life-years (QALYs) compared to mammography over 25 years of annual screening (MRI: 22.44 QALYs, mammography: 22.39 QALYs). However, 23,311 biopsies were performed following 239,906 breast MRI screenings while 11,487 biopsies were performed following 239,786 screening mammograms in a cohort of 10,000 women screened over 25 years. In univariate analysis, the true negative rates of breast MRI and mammography were the most influential variables in the model. In 10,000 probabilistic Monte Carlo simulations, MRI provided more QALYs in 72.7% of trials.

Conclusions: Screening women at high risk for breast cancer with breast MRI appears to be more effective than screening with mammography, despite the adverse effects of additional breast biopsies for false positive test results. Future analyses need to address the cost associated with MRI screening and diagnostic biopsies to ascertain whether this strategy constitutes an improvement over mammography for screening high risk women.