Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Mar 1;114(5):590-6.
doi: 10.1038/bjc.2016.8. Epub 2016 Feb 2.

Effect of organised mammography screening on stage-specific incidence in Norway: population study

Mette L Lousdal  1 , Ivar S Kristiansen  2 , Bjørn Møller  3 , Henrik Støvring  1
Affiliations

Effect of organised mammography screening on stage-specific incidence in Norway: population study

Mette L Lousdal et al. Br J Cancer. .

Abstract

Background: We aimed to estimate the effect of organised mammography screening on breast cancer stage distribution by comparing changes in women eligible for screening, based on birth cohort, to the concurrent changes in younger, ineligible women.

Methods: In an open cohort study in Norway, which introduced national mammography screening county-by-county from 1995 to 2004, we identified women (n=49 883) diagnosed with in situ or invasive breast cancer (ICD10 codes: D05 or C50) during the period 1987-2011 and born between 1917 and 1980. We estimated relative incidence rate ratios (rIRRs) comparing the development in the screening vs historic group to the younger vs younger historic group.

Results: Including the compensatory drop, eligible women experienced a 68% higher increase in localised cancers (rIRR=1.68, 95% confidence interval (CI): 1.51-1.87) than younger women, while the increase in incidence of advanced cancers was similar (rIRR=1.11, 95% CI: 0.90-1.36). Excluding the prevalence round, eligible women experienced a 60% higher increase in localised cancers (rIRR=1.60, 95% CI: 1.42-1.79), while the increase in incidence of advanced cancers remained similar (rIRR=1.08, 95% CI: 0.86-1.35).

Conclusions: Introduction of organised mammography screening was followed by a significant increase in localised and no change in advanced-stage cancers in women eligible for screening relative to younger, ineligible women.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Study design illustrated for the county of Oslo, where screening was introduced on 8 January 1996. Women are eligible for screening based on birth cohorts and programme start. Younger, ineligible women are below the age of screening. (A) Follow-up ends at the upper age limit for screening. (B) Follow-up of birth cohorts is continued to include the compensatory drop.
Figure 2
Figure 2
Annual absolute incidence over time in the county of Oslo, 1987–2011. The vertical line indicates introduction of screening.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Autier P (2013) Mammography screening before introduction of the national breast screening programme in Norway. Int J Cancer 132: 1721–1722. - PubMed
    1. Autier P, Boniol M (2012) Breast cancer screening: evidence of benefit depends on the method used. BMC Med 10: 163. - PMC - PubMed
    1. Autier P, Boniol M, Middleton R, Doré JF, Héry C, Zheng T, Gavin A (2011) Advanced breast cancer incidence following population-based mammographic screening. Ann Oncol 22: 1726–1735. - PMC - PubMed
    1. Biesheuvel C, Barratt A, Howard K, Houssami N, Irwig L (2007) Effects of study methods and biases on estimates of invasive breast cancer overdetection with mammography screening: a systematic review. Lancet Oncol 8: 1129–1138. - PubMed
    1. Black WC, Welch HG (1993) Advances in diagnostic imaging and overestimations of disease prevalence and the benefits of therapy. N Engl J Med 328: 1237–1243. - PubMed

Publication types

MeSH terms