Table 2.
Parameter | Description | Conditional on | Levels that influence parameter |
Incidence from age–period–cohort model | Incidence | Age, race, breast density, birth cohort | Ecological forces that affect risk behavior (eg, reproductive forces, trends in smoking post-WWII) Ecological factors that affect hormonal exposures Individual-level factors affecting risk such as family history and diet |
Population birth distribution | Probability distribution of birth-years in US population | Race | Ecological factors affecting diffusion of contraception; policies about use of contraception |
Non-breast cancer mortality | All-cause mortality exclusive of deaths from breast cancer | Race, age, birth cohort | Ecological factors affecting mortality such as occupations, insurance Individual factors related to social class, health habits |
Unscreened stage (or tumor size) distribution | Distribution of stages (or sizes) of tumors diagnosed in the absence of screening | Race, age | Biological scale factors related to cellular and molecular aspects of cancer progression |
Dwell-time distributions | Mean in stage and in preclinical state (sojourn time) | Age | Unobservable biological level of cellular and molecular events Interactions of biological levels with individual-level health behaviors and exposures that may modify biological processes |
Screened stage distribution | Distribution of stages of tumors that are screen-diagnosed by each test | Race, age, and first-vs-later screen | Ecological factors affecting structure of care, policies regarding insurance coverage, and access to screening and diagnostic services Individual factors related to adherence to screening use and diagnostic follow-up Biological level related to ability of technology to detect tissue changes related to cancer |
Screening dissemination | Distribution by cohort, age, time period | Cohort, age, calendar year | Ecological factors affecting structure of care, policies regarding insurance coverage, and access to screening and diagnostic services Individual factors related to adherence to screening use and diagnostic follow-up |
Operating characteristics | Sensitivity and specificity, initial and later screens | Race, age, tumor size, density | Ecological-level factors that affect the quality of screening facilities Population level related to training and skill of radiologists Biological level related to ability of technology to detect tissue changes related to cancer |
Screening-induced care | Biopsies and other diagnostic tests | Age | Ecological level in access to care Individual level in adherence and health seeking behaviors |
HR/HER2 distribution | Probabilities of tumors exhibiting ER and HER2 positivity | Race, age, stage/size at diagnosis | Individual level in health behaviors increasing risk of particular tumors (largely unknown at present) Biological level of cellular and genetic processes that lead to different types of tumors |
Treatment dissemination | Probability distribution of treatment regimens | Race, age, year, stage, ER/HER2 | Ecological level in access to care Individual level in adherence and health-seeking behaviors |
Natural history survival | Survival functions before use of adjuvant Rx | Race, age, stage | Biological level of unobservable natural history of disease in the absence of intervention |
Treatment effectiveness | Hazard ratios for regimens; modifies survival without Rx | Race, age, Rx, stage, ER/HER2 | Ecological level in access to treatment and quality of treatment Individual level in adherence to treatment regimen Biological levels of effects of treatments on cellular and molecular processes of carcinogenesis and metastasis |
Quality of life | Utility for each state | Age, stage | Ecological level of societal perspectives Individual-level preferences |
ER = estrogen receptor; HR = hormone receptor; WWII = World War II.