Women's Health

Model shows contribution of mammography screening and adjuvant therapy to reducing breast cancer deaths from 1975 to 2000

The Wisconsin Breast Cancer Epidemiology Simulation Model estimates that mammography screening and adjuvant therapy helped reduce breast cancer deaths by an average of 35.5 percent from 1975 to 2000. Mammography screening alone reduced deaths an average of 17.9 percent, while the average reduction for adjuvant therapy alone was 20.3 percent. The different modes of adjuvant therapy, depending on cancer stage and year, included chemotherapy alone, tamoxifen alone for 2 years, tamoxifen alone for 5 years, chemotherapy and a 2-year course of tamoxifen, or chemotherapy and a 5-year course of tamoxifen.

The model was designed to replicate breast cancer incidence and mortality rates in a population with the size and age structure of the Wisconsin female population generalized to breast cancer epidemiology in the U.S. population from 1975 to 2000. The model simulated women individually from 1950 (or the year in which they were 20 years of age) until they died a simulated death, achieved age 100, or the simulated year 2000 was reached. The model simulated the natural history of breast cancer from occult onset to breast cancer death; detection of breast cancer by screening mammography or other diagnostic pathways; effectiveness of treatment of breast cancer and diffusion of adjuvant therapies over time; and death from non-breast cancer causes. The model assumed that in 1950 all women were free of breast cancer.

The model calculated age-specific incidence rates by stage and age-specific mortality rates. It may be helpful for addressing questions about the effectiveness of screening and treatment protocols, as well as estimating the benefits to women of specific ages and screening histories. The model was developed as part of the National Cancer Institute's Cancer Intervention and Surveillance Modeling Network. The study was supported in part by the Agency for Healthcare Research and Quality (T32 HS00083).

See "The Wisconsin breast cancer epidemiology simulation model," by Dennis G. Fryback, Ph.D., Natasha K. Stout, Ph.D., Majorie A. Rosenberg, Ph.D., F.S.A., and others, in the Journal of the National Cancer Institute Monographs 36, pp. 37-47, 2006.

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