Purpose:  Digital mammography's potential benefit over plain-film mammography may be restricted to women with higher breast density.  We estimated the cost-effectiveness of different strategies of digital and plain-film mammography.

Methods:  We created a Markov model of breast cancer screening and treatment using published estimates of breast cancer incidence, rates of adherence to both annual mammography recommendations and to follow-up after a positive mammogram, mammography operating characteristics for film and digital mammography, diagnostic testing strategies, utilities for different breast cancer states and costs for diagnostic and treatment procedures.  We also included annual transition rates among different breast cancer density states derived from a primarily Caucasian mammography registry.  We compared four strategies:  1) no mammography, 2) plain-film mammography for all women, 3) digital mammography for all women and 4) a breast density-dependent strategy using digital mammography for women when their breasts have high density and using plain-film mammography for women when their breasts have low density.  For each strategy, every woman diagnosed with breast cancer underwent annual surveillance for recurrent cancer.  We used the third-party payer perspective.  We tracked the costs and benefits of 250 groups of 1000 women in each strategy from age 40 to 76.  We discounted costs and benefits by 3% annually.

Results:  In the absence of screening mammography, 1000 women would accumulate 21,049 QALYs at a median cost of $898,917.  Adding screening plain-film mammography added ten QALYs at a cost of $278,822.  Substituting digital mammography for plain-film mammography added eight QALYs for an additional $189,068 (ICER $23,634/QALY).  The figure below compares the costs and effectiveness of the women using plain-film mammography (circles) and the women using digital mammography (triangles).  Each hollow shape represents a cohort of 1000 women and the solid shape is the strategy's median value.  The breast density-dependent strategy provided the same number QALYs as the digital mammography strategy, but cost $94,270 less.