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Volume 6 Supplement 1

Symposium Mammographicum 2004

  • Oral presentation
  • Open Access

The impact of mammographic screening on breast cancer mortality: overview of the evidence so far

  • 1 and
  • 2
Breast Cancer Research20046 (Suppl 1) :P7

  • Published:


  • Breast Cancer
  • Confidence Interval
  • Cohort Study
  • Cancer Research
  • Search Strategy

Controversy remains over the scale of benefit women can expect from attending mammographic screening programs. We review the evidence, presenting (1) an updated meta-analysis of the latest results from the randomised trials and (2) an overview of the non-randomised evidence.

After eight randomised trials with 12–20 years follow-up, the pooled results show a significant 20% (95% confidence interval [CI]: 14%, 27%) reduction in breast cancer mortality associated with invitation to screening. When stratified by age, the reductions were 15% (95% CI: 2%, 27%) for women aged under 50 and 22% (95% CI: 14%, 30%) for women aged 50–74.

The search strategy for nonrandomised evidence relating to mortality yielded 12 descriptive studies, seven case-series, six case–control, eight cohort and three nonrandomised comparative studies. All indicated some benefit associated with screening. Overall, the case–control studies indicated a 35% (95% CI: 20%, 48%) reduction in breast cancer mortality associated with screening. The corresponding reduction for cohort studies was 44% (95% CI: 39%, 48%) for screening and 31% (95% CI: 21%, 40%) for invitation.

The majority of evidence from randomised and nonrandomised sources demonstrates a reduction in breast cancer mortality with screening. Studies should continue to monitor the benefit of screening programmes, taking care to address potential forms of bias.

Authors’ Affiliations

Cancer Research UK, London, UK
Queen Mary University of London, UK


© BioMed Central 2004