Modelling the analysis of breast cancer screening programmes: sensitivity, lead time and predictive value in the...

Statistical indicators of early efficacy were estimated in the Florence District Programme where breast cancer screening has been carried out since 1970. Analysis of screen-detected and interval cancer data by means of statistical modelling using GLIM allowed us to estimate the mean sojourn time (1.91 and 3.97 years in 40-49 and 50-69 year old women respectively), sensitivity (about 90% for those aged 50-69) and predictive value at the prevalence screening test (about 100%). Results were compared with estimates of the same parameters in the Health Insurance Plan and Swedish Two County studies.