Organised mammography screening reduces breast cancer mortality: A cohort study from Finland

Abstract

We evaluated the effectiveness and the efficacy of populationbased mammography programme in Finland, and explored associations between the screening performance and the screening efficacy. The main outcome, incidence-based mortality from breast cancer, was estimated by invitation, participation, age at death, and screening centres categorised by recall rates. The study was based on an individual followup of screening invitees and participants from 1992 to 2003. The coverage of screening invitations was 95% among 50-59 years old women, and 20-40% among women aged 60-69 years. We compared observed deaths from breast cancer to expected breast cancer deaths without screening in ages 50-69 at death. The observed deaths were obtained from a cohort of individual invitees (n 5 361,848). The expected deaths were defined by modelling breast cancer mortality from 1974 to 1985 and 1992 to 2003 at population level. The population data were derived from the same municipalities (n 5 260) that were incorporated into the cohort. The breast cancer mortality among the invited women was reduced by 22% (relative risk 0.78, 95% confidence interval 0.70-0.87). After adjusting for the self-selection, the efficacy among the participants was 28% (0.72, 0.56-0.88). No clear association between the recall rates and the screening efficacy was observed. The organised mammography screening in Finland is effective. The relationship between the estimates of process and outcome of mammography is not yet straightforward: effectiveness and efficacy remain the best estimates for evaluating the success of mammography screening. ' 2007 Wiley-Liss, Inc.Key words: effectiveness; mammography; screening; breast cancer; epidemiology Several randomised trials have reported effectiveness of screening for breast cancer. The combined results showed 25% reduction in breast cancer mortality among women aged 50-69 years at randomisation. 1 The cohort studies on service screening from Sweden and Denmark have reported effects at similar level. [2][3][4] In Finland, a pilot study on breast cancer screening began in 1982. 5 The nationwide mammography programme started in 1987 and it was implemented gradually. The effectiveness for the first 5 years of the programme was analysed using randomised birth cohorts. 6 The study demonstrated a nonsignificant, 24% reduction in breast cancer mortality associated with invitation to screening.The adaptation of results from randomised trials to routine screening is not self-evident. The performance and validity of mammography screening within and between the European programmes have varied widely, 7-9 suggesting differences also in the effectiveness and adverse effects of screening. There has also been variation in the screening policies. 1 The effectiveness of mammography screening has been debated during the last years, 10-12 and the impact of population-based screening on breast cancer mortality has been analysed in many European countries. [2][3][4]6,[13][14][15] The main aim of the current study was to analyse the effectiv...

Breast Cancer Mortality in Mammographic Screening in Europe: A Review of Incidence-Based Mortality Studies

“…Most of the study population in Anttila et al 19 was included in Sarkeala et al 9 An overlap similar of that seen in Finland was found for the six Swedish publications, with the 13-area study 18 giving the best coverage of the Swedish data.…”

“…Three studies were from Sweden, 15,16,18 three from Finland 8,9,19 and one from Spain 17 ( Table 3). In this group, all RRs were statistically significant ranging from 0.52 to 0.82.…”

“…Ancelle-Park R (F) 1 , Armaroli P (I) 2 , Ascunce N (E) 3 , Bisanti L (I) 4 , Bellisario C (I) 2 , Broeders M (NL) 5 , Cogo C (I) 6 , De Koning H (NL) 7 , Duffy SW (UK) 8 , Frigerio A (I) 2 , Giordano L (I) 2 , Hofvind S (N) 9 , Jonsson H (S) 10 , Lynge E (DK) 11 , Massat N (UK) 8 , Miccinesi G (I) 12 , Moss S (UK) 8 , Naldoni C (I) 13 , Njor S (DK) 11 , Nyströ m L (S) 14 , Paap E (NL) 5 , Paci E (I) 12 , Patnick J (UK) 15 , Ponti A (I) 2 , Puliti D (I) 12 , Segnan N (I) 2 , Von Karsa L (D) 16 , Tö rnberg S (S) 17 , Zappa M (I) 12 , Zorzi M (I) The search strategy retrieved a total of 2432 papers. After inspection of titles and abstract, according to the criteria's described in the article, we judged 98 papers as relevant.…”

Mortalidad por cáncer de mama: evolución en España y sus comunidades autónomas durante el período 1980-2005

“…Inicialmente este impacto estaría suavizado por la baja participación de las primeras rondas, así como por la mortalidad atribuible a los casos diagnosticados en los años inmediatamente anteriores al inicio del programa. En España, según nuestro estudio y como en la mayoría de los países desarrollados, el descenso en la mortalidad se produce antes de lo esperado para poder atribuirlo exclusivamente al cribado poblacional [17][18][19] .…”

Development of terminology for mammographic techniques for radiological technologists

“…Mammography is the best form of examination for the early detection of breast cancer because it can detect non-palpable microcalcifications, and it has been reported that mammography is effective in decreasing the mortality due to breast cancer [2,3]. Because of variations in breast compositions and psychological burdens (e.g., exposure of the upper body, concern over radiation exposure and compression of the breast, etc.…”