AGE-SPECIFIC SENSITIVITY AND SOJOURN TIME IN A BREAST-CANCER SCREENING-PROGRAM (DOM) IN THE NETHERLANDS - A COMPARISON OF DIFFERENT METHODS

Study objective - To estimate age dependent sensitivity and sojourn ti me in a breast cancer screening programme by different methods. Popula tion and methods - The study population comprised women participating in the DOM project - the Utrecht screening programme for the early det ection of breast cancer. Breast cancer screening prevalence data and i ncidence rates after a negative screen were used to estimate age speci fic sensitivity and mean sojourn time by different methods. Main resul ts - Maximum likelihood estimates of the mean sojourn time varied from one year for women aged 40-49 years to three years for women over the age of 54. Sensitivity was calculated by two different methods. Both pointed to a high sensitivity (around 100%) in the age groups 40-49 an d over 55 years. For women aged 50-54, the sensitivity varied from 63% to 100%, depending on the method used and the value of the baseline i ncidence rate. Conclusions - Different methods of estimating sensitivi ty pointed at an acceptable level in women over and under 50 years of age. Sojourn time, and thus the tumour growth rate, seemed to be age d ependent. This could mean that the until now disappointing screening r esults in women under 50 years of age are not so much a result of low sensitivity as of a relatively high tumour growth rate in younger wome n.