Fig. 1.

Model diagram for simulating individuals. LC, lung cancer. White boxes represent health states; grey boxes and arrows represent events. An individual begins the simulation without clinically diagnosed lung cancer, because they do not have lung cancer or they have occult lung cancer (health states on the left hand side). He/she is immediately at risk of incidental development of lung cancer, preclinical progression of the occult tumour, detection or death from other causes. It is assumed that death from lung cancer is preceded by a diagnosis. Following detection, the individual is again at risk of progression or death, now from either from lung cancer or other causes