Optimisation of mammographic breast cancer screening using a computer simulation model.

To optimise breast cancer screening protocols, risk (induction of fatal tumors) versus benefit (reduction in the number of fatal tumors) analyses are performed for a simulated stable Swedish female population, using the Model for evaluation of Breast cancer Screening (MBS). The present study comprises, the influences of various screening parameters, i.e. ages at which screening is started and stopped, interval period between successive sessions, tumor detection limits for screening and average glandular dose per screening session. When the results of the present study are expressed in terms of numbers of fatal breast tumors, it appears that starting and stopping ages for screening of 40 and 80 years, respectively, seem realistic. An increased screening frequency results in a larger reduction of breast cancer mortality. This reduction is significant for ages between 40 and 51 years but only marginal for ages above 70 years. High resolution screening, i.e., the detection of tumors at smaller size, results in a larger benefit but does not indicate a younger age for starting of screening. The average glandular dose per screening session does only influence the risks of screening. As separate risk and benefit results are presented, a change in average glandular dose on the total effect of screening can easily be calculated.