Chapter 1: Modeling the Impact of Adjuvant Therapy and Screening Mammography on U.S. Breast Cancer Mortality Between 1975 and 2000: Introduction to the Problem

The Cancer Intervention and Surveillance Modeling Network (CISNET) ( http://cisnet.cancer.gov ) is a consortium of National Cancer Institute (NCI) – sponsored investigators whose focus is modeling the impact of cancer control interventions on population trends in incidence and mortality for breast, prostate, colorectal, and lung cancer. These models are also used to project future trends and to help determine optimal cancer control strategies. Although each investigator has pursued research questions of individual interest, the breast group, consisting of seven principal investigators and their coinvestigators, agreed to collaborate to answer the following question: “ What is the Impact of Adjuvant Therapy and Screening Mammography on U.S. Breast Cancer Mortality, 1975 – 2000 ” ? The idea of this comparative model ing approach was to have each group synthesize existing, and sometimes confl icting, knowledge to build models of breast cancer treatment and screening, using certain specifi ed common population-level inputs. Because there was considerable room for variation in approaches, the desire was to use the palette of modeling to bring into better focus areas of consensus and disagreement. U.S. breast cancer mortality for women was rising slightly until 1990 but since declined 20% through 2000 and continued to decline a total of 23% (about 2.3% per year) through 2002 ( 1 ) . To better understand why these declines have occurred.(i.e., where we have been) and to target new cancer control strategies (i.e., where we are going), decomposing the population impact of interventions that began in the 1970s and 1980s is important. Population impact represents the fi nal phase of cancer research, because even if interventions have been evaluated in randomized controlled trials (RCTs), its impact in the population setting (effectiveness) may differ from that in a trial setting (effi cacy), and the dissemination of the intervention in the target population may be less than complete. The consortium used a common set of Chapter 1: Modeling the Impact of Adjuvant Therapy and Screening Mammography on U.S.