4 augustus 2011: Bron: WHO en British Journal of Medicin

Periodieke screening van de vrouwen in de leeftijd na de overgang door o.a. een mammografie blijkt geen of weinig invloed te hebben op de uiteindelijke overlevingskansen voor die vrouwen die uiteindelijk borstkanker krijgen. Dit blijkt uit een onderzoek dat de WHO deed op basis van hun beschikbare data. De WHO vergeleek de gegevens van borstkanker incidentie en sterfte tussen drie paar landen die onafhankelijk van elkaar periodieke screening met minimaal een tussenperiode van 10 jaar of meer vroeger of later invoerden. Zo werden de gegevens van Nederland en Belgie en Vlaanderen vergeleken waarbij Nederland al in 1989 begon met screening en in Vlaanderen pas vanaf 2001. Het verschil tussen Vlaanderen en Nederland in sterfte was slechts 1 procent. Vergelijkbare resultaten werden gezien tussen Noorwegen en Zweden en Ierland en Noord-Ierland. Dat er een kleine vooruitgang is geboekt in de 5-jaars overleving van borstkanker lijkt te worden veroorzaakt door betere behandelmethoden, aldus de onderzoekers, maar zij kunnen dit niet staven met bewijzen. Hieronder het deel van de studie met cijfers uit Nederland en Belgie en Vlaanderen. Het volledige studierapport is vrij in te zien als u hier klikt op de website van het British Journal of Medicin

Breast cancer mortality in neighbouring European countries with different levels of screening but similar access to treatment: trend analysis of WHO mortality database

Source: British Journal of Medicin

Eerst de gegevens voor Nederland en Belgie en Vlaanderen, daaronder het abstract van de volledige studie:

The Netherlands and Belgium

In the Netherlands, a national organised mammography screening programme was initiated in 1989 (table 1). After gradual implementation, the programme reached full coverage in 1997.15 16 Women aged 50-69 are invited to mammography every two years, and since 1998 women aged 70-74 are also invited. Figure 2⇓ shows that participation in screening gradually increased from 1989 to 1996, and after 1997 it has remained constant at around 70-79%. Non-organised screening is uncommon.

View larger version:

In a new window

Download as PowerPoint Slide

Fig 2 Participation in mammography screening and age adjusted (European standardised rates) breast cancer mortality in women of all ages in the Netherlands and Belgium

In Belgium, breast screening was left to the discretion of the women and doctors until 2001, after which a national screening programme was established. Population surveys before 1999 suggested that less than 30% of women in the 50-69 year age group had undergone mammography during the past two years (for screening or diagnostic purposes).17 Around 2000, about 30% of women aged 50-69 had undergone screening or diagnostic mammography in the past two years.18 19 By around 2005 this proportion had increased to about 59% (fig 2). At that time two thirds of screening examinations were done as part of the organised programme in Flanders, and for less than one sixth in Brussels and Wallonia. Participation in screening (organised and non-organised) in Flanders was low until about 2002-3, and by 2004-6 it was still below the coverage in the Netherlands in 1997 (fig 2).

In the Netherlands the overall reduction in breast cancer mortality from 1989 to 2006 was slightly greater than in Belgium (25.0% v 19.9%) but did not differ noticeably from Flanders (25.0% v 24.6%; table 2 and fig 2).

Breast cancer mortality in neighbouring European countries with different levels of screening but similar access to treatment: trend analysis of WHO mortality database

OPEN ACCESS

Philippe Autier, research director1,
Mathieu Boniol, senior statistician1,
Anna Gavin, director2,
Lars J Vatten, professor3

+ Author Affiliations

¹International Prevention Research Institute, 95 Cours Lafayette, 69006 Lyon, France
²Northern Ireland Cancer Registry, Belfast, Northern Ireland, UK
³Department of Public Health, Norwegian University of Science and Technology, Trondheim, Norway

Correspondence to: P Autier philippe.autier@i-pri.org

Next Section

Abstract

Objective To compare trends in breast cancer mortality within three pairs of neighbouring European countries in relation to implementation of screening.

Design Retrospective trend analysis.

Setting Three country pairs (Northern Ireland (United Kingdom) v Republic of Ireland, the Netherlands v Belgium and Flanders (Belgian region south of the Netherlands), and Sweden v Norway).

Data sources WHO mortality database on cause of death and data sources on mammography screening, cancer treatment, and risk factors for breast cancer mortality.

Main outcome measures Changes in breast cancer mortality calculated from linear regressions of log transformed, age adjusted death rates. Joinpoint analysis was used to identify the year when trends in mortality for all ages began to change.

Results From 1989 to 2006, deaths from breast cancer decreased by 29% in Northern Ireland and by 26% in the Republic of Ireland; by 25% in the Netherlands and by 20% in Belgium and 25% in Flanders; and by 16% in Sweden and by 24% in Norway. The time trend and year of downward inflexion were similar between Northern Ireland and the Republic of Ireland and between the Netherlands and Flanders. In Sweden, mortality rates have steadily decreased since 1972, with no downward inflexion until 2006. Countries of each pair had similar healthcare services and prevalence of risk factors for breast cancer mortality but differing implementation of mammography screening, with a gap of about 10-15 years.

Conclusions The contrast between the time differences in implementation of mammography screening and the similarity in reductions in mortality between the country pairs suggest that screening did not play a direct part in the reductions in breast cancer mortality.

bevolkinsonderzoek, statistiek, sterftecijfers, borstkanker, mammografie, screening