[Evaluation of screening methods in the detection of breast cancer].

The paper discusses such theoretical aspects of screening as lead time, tumor doubling time and duration of presymptomatic period. A procedure for calculating indexes of effectiveness of screening in a population (sensitivity, specificity and predictive value of positive and negative results of screening) is suggested. The data available at the All-Union Center for Research on Breast Cancer at the N. N. Petrov Research Institute of Oncology of the USSR Ministry of Health were used to calculate lead time which appeared to be 3.16 years. It was found that screening can establish the diagnosis of breast cancer as early as 3 years prior to its clinical manifestations.