Armitage-Doll two-stage model: implications and extension.

The objective of this paper is twofold: (1) to provide insight on the simplified MVK model of carcinogenesis (a model proposed by Moolgavkar and colleagues) by revealing the relationship between the Armitage-Doll two-stage model and the simplified MVK model; and (2) to extend the Armitage-Doll two-stage model to one with time-varying (piece-wise constant) parameters. It is shown that the simplified MVK model is a special case of the Armitage-Doll two-stage model, and many applications of the simplified MVK model involving intermittent exposures or exposures to different compounds in different time periods can be derived easily from the Armitage-Doll two-stage model with piece-wise constant parameters. The limitations of the Armitage-Doll two-stage model are discussed.