CAD falls within cost-effectiveness range

Combining computer-aided detection with screening mammography increases marginal costs per year of life saved by 19%. This is well within the cost-effectiveness range of other medical procedures, according to a study presented Monday.

An estimated 25% to 30% of all screening mammography exams performed in the U.S. are interpreted with the help of CAD, but to date no study has evaluated the cost-effectiveness its use, said Dr. Karen K. Lindfors, chief of breast imaging at the University of California, Davis.

Using a computer model based on published data, Lindfors and colleagues evaluated the impact of CAD costs by comparing three hypothetical groups of women aged 40 to 79: one undergoing screening mammography with CAD, one undergoing screening mammography without CAD, and a third undergoing observation without screening.

The computer model was based on cancer detection rates arising out of a prospective study of screening mammography and CAD published in 2001 by Dr. Timothy Freer.

In Freer's study, 12,860 screening mammograms were interpreted with the assistance of CAD over a one-year period. Cancer detection increased by 19.5%, and the proportion of early stage (0 and I) malignancies detected rose from 73% to 78% (Radiology 2001;220:781-786). Lindfors also based probability of outcomes on the Freer study.

Survival rates were modeled on five-year statistics generated by the American Cancer Society. Costs for screening mammography and CAD were based on 2003 average global Medicare reimbursements of $82.77 and $19.13, respectively.

Lindfors found that adding CAD to a mammography screening program results in a marginal cost per year of life saved (MCYLS) of $19,508.

The MCYLS to provide screening mammography without CAD compared with observation only is $16,023, she said.

"While the MCYLS that we found does fall within the accepted range for other medical procedures, a magnitude change in the cancer detection rate with CAD could dramatically increase its cost-effectiveness," Lindfors said.

Such data could be forthcoming, she said, citing research in press by Dr. Tommy E. Cupples of the South Carolina Comprehensive Breast Center that will report a MCYLS of $7933 when CAD is paired with screening mammography.