Optimal Scheduling of Medical Exams: The Case of Breast Cancer

Giovanni Parmigiani
Duke University

Nov 30 1990

Screening for early detection is currently one of the most effective ways to control breast cancer. As the incidence of breast cancer is strongly dependent on age, the question arises of how such dependence should affect the spacings between screening times. Various facets of this general question, such as the appropriateness of screening before age 50 and the efficacy of biannual examinations, have been at the center of the debate on breast cancer screening in the last few years.
This paper illustrates the use of a decision theoretic model for determining the best sequence of examination ages for the early detection of breast cancer. Policies are evaluated on the bases of the expected number of examinations involved and of the expected reduction in mortality. Trade-off curves between these two quantities are calculated for the optimal schedule as well as the optimal periodic schedule with arbitrary age of first screen; the results are used to compare the available alternatives, including the policies currently recommended by various scientific and professional organizations. One indication emerging from the analysis is that periodic screening examinations, if properly scheduled, do not entail a substantially higher risk than optimally scheduled examinations. Screening before age 50, biannual examinations, and the impact of improved sensitivity of mammographies are also discussed.


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