Performance indicators evaluation of the population-based breast cancer screening programme in Northern Portugal...

To evaluate the first 10 years of operation of the population-based breast cancer screening programme implemented in the Northern Region of Portugal, using selected recommended standard performance indicators.

Data from women aged 50-69 screened with two-view mammography, biennially, in the period 2000-2009, were included. Main performance indicators were compared with the recommended levels of the European Guidelines.

A total of 202,039 screening examinations were performed, 71,731 (35.5%) in the initial screening and 130,308 (64.5%) in the subsequent screening. Coverage rate by examination reached 74.3% of the target population, in the last period evaluated. Recall rates were 8.1% and 2.4% and cancer detection rates were 4.4/1000 and 2.9/1000 respectively, for initial and subsequent screenings. The breast cancer detection rate, expressed as a multiple of the background expected incidence was 3.1 in initial screen and 2.2 in subsequent screen. The incidence of invasive interval cancers met the desirable recommended levels both the first and second years since last screening examination, in the initial and subsequent screenings. Invasive tumours <15mm were 50.4% and 53.8% of the invasive cancers detected in initial and subsequent screenings. Less favourable size, grading and biomarkers expression were found in interval cancers compared to screen-detected cancers.

Breast cancer screening programme in the Northern Region of Portugal was well accepted by the population. Most of the performance indicators were consistent with the desirable levels of the European Guidelines, which indicate an effective screening programme. Future research should verify the consistency of some of these results by using updated information from a larger population.