Modelling the likely effect of the increase of the upper age limit from 70 to 73 for breast screening in the UK National Programme

Duffy, Sasieni, Olsen and Cafferty have a new paper in Statistical Methods in Medical Research. This considers the possible effect of increasing the upper age of breast cancer screening from 70 years to 73 years. Two approaches are taken. Firstly, a 4-state time homogeneous Markov model is considered, with the states representing healthy, asymptomatic breast cancer (detectable by screening), symptomatic breast cancer and death. Secondly, a discrete-time model where incidence of breast cancer and mortality from other causes is assumed to be uniform in each year of age. Other rates are still considered to be time homogeneous. The benefit in life years gained up to 88 years of age is considered. The intensities are estimated from external data. Both approaches give similar results, with about 1 life-year gained per 1000 women screened.