Abstract
A compartment model of carcinogenesis which describes separately the process of smoking-related lung cancer and that of smoking-unrelated lung cancer is presented. This model is well fitted to the equation representing the lung cancer incidence rate of the British physicians' cohort. The compartment model is shown to agree with the frozen type of incidence curve among ex-smokers. This model is biologically plausible in the context of the mechanism of carcinogenesis. For planning public health policies in a community and for health education based on smoking data, we calculated the change of risk after the cessation of smoking.
