Process indicators from ten centres in the Finnish breast cancer screening programme from 1991 to 2000

The aim of this study was to evaluate the quality of the Finnish mammography programme by assessing process indicators from 10 screening centres using data from the first and subsequent screens. We compared these screen-specific indicators with European standards and results from countries with similar screening protocols. Ten Finnish centres invited approximately 1,000,000 women from 1991-2000. Women were mainly 50-64 years old. Mean compliance amongst this age group was 90% at the first and 93% at subsequent screens. The corresponding recall rates were 4.6% and 2.3%, respectively. The average breast cancer detection rates were 0.44% and 0.36%, respectively. The positive predictive values (PPVs) of mammography at the first and subsequent screens were 10% (range 7-20%) and 16% (range 12-31%), and the corresponding benign to malignant (B:M) biopsy ratios were 1:1 (range 0.5-1.8:1) and 0.4:1 (range 0.3-0.8:1). The PPV of mammography increased significantly during the study period, and the average process indicators fulfilled the criteria of the European community for the most part. However, the variation in PPVs was wide, as has been seen for other European mammography programmes, indicating meaningful differences in diagnostic criteria and potential adverse effects.