Abstract
Current proposals for a monitoring and evaluation system in breast cancer screening programmes focus on mortality reduction. Here emphasis is laid on the prevention of too high a number of false-positive screening results, i.e. no subsequent demonstration of malignancy. By comparing the specificity of the screening test, the positive predictive value and the detection rate with reference values, the screening performance can be measured in a very early phase of the programme, even before the registration results on interval cancers become available. The proposed average reference values for the first screening round are 99.2%, 40% and 5.4/1000, respectively. Measures specifically for the age groups 45-49, 50-59 and 60-69 will be given, thus allowing improvements to be made if necessary.
Highlights
The aim of screening for breast cancer is to reduce breast cancer mortality. This effort should not lead to an excess of false positive screening test results, which invariably involve unnecessary diagnostic work-up
It is important that screening programmes are closely monitored, and have a good system for quality control
Because the anticipated effect on breast cancer mortality will probably take 10 years to emerge and will only occur if short term reference values are met, quality parameters have been proposed to be evaluated from the very start of the programme (Day et al, 1989)
Summary
The proposals concern modified outcomes from the Nijmegen screening programme (Peeters et al, 1989a) and are comparable to those observed recently in the Swedish W&E trial (Tabair et al, 1989) In both programmes a breast cancer mortality reduction of more than 40% has been observed. If the specificity does not meet the reference value, improvements have to be made irrespective of the other control outcomes In such a screening set-up the proportion of healthy women with a positive screening test is not acceptable. In a new screening centre the lowest acceptable value in this age group might be set at 99.2%, the reference value This would allow the screening test to mark positive a maximum of 0.8% of the
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