Performance indicators evaluation of the population-based breast cancer screening programme in Northern Portugal using the European Guidelines Maria José Bento a,b, *, Guilherme Gonçalves a , Ana Aguiar c , Clara Castro b , Vitor Veloso c , Vítor Rodrigues d,e a Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua de Jorge Viterbo, n  228, 4050-313 Porto, Portugal b Epidemiology Unit, Portuguese Oncology Institute, Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto, Portugal c Portuguese Cancer League – North Branch, Porto Estrada Circunv. 6657, 4200-000 Porto, Portugal d Faculty of Medicine, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal e Portuguese Cancer League – Centre Branch, Coimbra Rua Dr. Antonio Jose Almeida 329, 2  -pt 56, 3000-045 Coimbra, Portugal A R T I C L E I N F O Article history: Received 26 April 2015 Received in revised form 8 August 2015 Accepted 12 August 2015 Available online 24 August 2015 Keywords: Breast cancer Performance indicators Population-based screening Mammography A B S T R A C T Objective: 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. Methods: 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. Results: 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 <15 mm 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. Conclusions: 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. ã 2015 Elsevier Ltd. All rights reserved. 1. Introduction The main objective of breast cancer screening is to reduce mortality due to the disease. That is achieved by identifying breast cancer at a stage when it is more curable and the probability of the disease being disseminated is smaller [1–4]. Because screening programmes must be operating for many years before breast cancer mortality reduction can be verified, some early surrogate measures are considered valuable indicators of future changes in mortality rates [5]. In 2006, the European Union published the 4th edition of the European Guidelines on Quality Assurance in Breast Cancer Screening and Diagnosis [6] that have been used in the evaluation of specific European programmes [7,8]. A good screening programme is a complexorganisation with multiple steps encompassing the entire screening process and, to maintain a high-quality service, it requires continuous supervision and regular reporting of rigorous scientific * Corresponding author: Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua de Jorge Viterbo, n  228, 4050-313 Porto, Portugal. Fax: +351 225084004. E-mail addresses: mjbento@icbas.up.pt, mjbento@ipoporto.min-saude.pt (M.J. Bento), aggoncalves@icbas.up.pt (G. Gonçalves), anateresaaguiar@netcabo.pt (A. Aguiar), clara.castro@ipoporto.min-saude.pt (C. Castro), presidente.nrnorte@ligacontracancro.pt (V. Veloso), vrodrigues@netcabo.pt (V. Rodrigues). http://dx.doi.org/10.1016/j.canep.2015.08.004 1877-7821/ ã 2015 Elsevier Ltd. All rights reserved. Cancer Epidemiology 39 (2015) 783–789 Contents lists available at ScienceDirect Cancer Epidemiology The International Journal of Cancer Epidemiology, Detection, and Prevention journa l homepage: www.cancerepidemiology.net