Table 1.

Breast Cancer Natural History Input Parameters Estimated via Model Calibration and Their Best-fitting Values

Parameter Name	Description	Value in the “Best” Vector
LMP Fraction	Proportion of tumors with limited malignant potential (LMP)	42%
Max LMP size	The maximum size for LMP tumors	1 cm
LMP Dwell Time	After an LMP tumor reaches Max LMP size, this parameter represents the time for this LMP tumor to regress or become undetectable	2 years
Onset Proportion	Ratio of biologic onset rate of non LMP tumors to APC predicted incidence rate in the absence of screening	90%
Onset Lag	Time between APC predicted incidence of a tumor and the inception of the tumor in the model	3 years
Mean Gamma	Mean value of the Gompertzian tumor growth variable (α) that is distributed with Gamma distribution	0.12
Variance Growth	Variance of the Gompertzian tumor growth variable (α) that is distributed with Gamma distribution	0.012
In situ boundary	The diameter below which a tumor is classified as in situ cancer if no lymph nodes are involved	0.95 cm
Percent aggressive	Percentage of non LMP tumors that are classified as regional cancers at onset	1%
Percent highly aggressive	Percentage of non LMP tumors that are classified as distant cancers at onset	2%

Abbreviations: APC, age period cohort; LMP, limited malignant potential.