Increasingly strong reduction in breast cancer mortality due to screening

Br J Cancer. 2011 Mar 15;104(6):910-4. doi: 10.1038/bjc.2011.44. Epub 2011 Feb 22.


Background: Favourable outcomes of breast cancer screening trials in the 1970s and 1980s resulted in the launch of population-based service screening programmes in many Western countries. We investigated whether improvements in mammography and treatment modalities have had an influence on the effectiveness of breast cancer screening from 1975 to 2008.

Methods: In Nijmegen, the Netherlands, 55,529 women received an invitation for screening between 1975 and 2008. We designed a case-referent study to evaluate the impact of mammographic screening on breast cancer mortality over time from 1975 to 2008. A total number of 282 breast cancer deaths were identified, and 1410 referents aged 50-69 were sampled from the population invited for screening. We estimated the effectiveness by calculating the odds ratio (OR) indicating the breast cancer death rate for screened vs unscreened women.

Results: The breast cancer death rate in the screened group over the complete period was 35% lower than in the unscreened group (OR=0.65; 95% CI=0.49-0.87). Analysis by calendar year showed an increasing effectiveness from a 28% reduction in breast cancer mortality in the period 1975-1991 (OR=0.72; 95% CI=0.47-1.09) to 65% in the period 1992-2008 (OR=0.35; 95% CI=0.19-0.64).

Conclusion: Our results show an increasingly strong reduction in breast cancer mortality over time because of mammographic screening.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Breast Neoplasms / diagnosis*
  • Breast Neoplasms / mortality*
  • Carcinoma / diagnosis*
  • Carcinoma / mortality*
  • Case-Control Studies
  • Down-Regulation
  • Early Detection of Cancer* / methods
  • Female
  • Humans
  • Mammography / methods
  • Mammography / statistics & numerical data
  • Mass Screening / methods
  • Middle Aged
  • Program Evaluation