Updated results of the Gothenburg Trial of Mammographic Screening

Authors

  • Nils G. Bjurstam MD, PhD,

    1. Department of Radiology, Sahlgrenska University Hospital, Sahlgrenska Academy at Göteborg University, Gothenburg, Sweden
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  • Lena M. Björneld RN,

    1. Department of Radiology, Sahlgrenska University Hospital, Sahlgrenska Academy at Göteborg University, Gothenburg, Sweden
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  • Stephen W. Duffy MSc

    Corresponding author
    1. Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, United Kingdom
    • Corresponding author: Stephen W. Duffy, MSc, Wolfson Institute of Preventive Medicine, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, United Kingdom; Fax: (011) 44 (0)20 7882 3890; s.w.duffy@qmul.ac.uk

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  • Nils Bjurstam was the principal investigator, initiated and supervised the study, and contributed to the informatics, analysis, interpretation, and drafting of the manuscript. Lena Björneld was responsible for the day-to-day management and conduct of the study and contributed to the informatics, analysis, interpretation, and drafting of the manuscript. Stephen W. Duffy was responsible for the statistical analysis and contributed to the analysis, interpretation, and drafting of the manuscript.

  • We thank Nick Day and Laszlo Tabar for their invaluable guidance at the time of setting up the trial. We thank all the professionals involved in the trial and the subjects who participated. Special thanks are due to the Swedish Overview Group and, in particular, Lennarth Nyström and Jan Frisell (among others) for their essential contributions to the informatics and follow-up of the Gothenburg trial.

Abstract

BACKGROUND

There remain uncertainties about age-specific effects of breast cancer screening on mortality due to the disease.

METHODS

In 1982, a randomized trial of mammographic screening every 18 months was started in Gothenburg, Sweden. Women between the ages of 39 and 49 years were randomized to an invitation to screening (intervention group; n = 11,792) or to usual care (the control group; n = 14,321). The corresponding numbers for women between the ages of 50 and 59 years were 10,112 and 15,997. Follow-up data for breast cancer mortality were available up to the end of 2007. Data were analyzed by Poisson regression with conservative variance estimates.

RESULTS

There were 79 breast cancer deaths in the intervention arm and 156 in the control arm, and this meant a significant 30% reduction in breast cancer mortality with the offer of screening (relative risk [RR], 0.70; 95% confidence interval [CI], 0.53-0.93; P = .01). In women aged 39 to 49 years, there was a significant 40% reduction in breast cancer mortality (RR, 0.60; 95% CI, 0.43-0.85; P = .003). In the 50- to 59-year age group, there was a nonsignificant 18% breast cancer mortality reduction (RR, 0.82; 95% CI, 0.54-1.26; P = .4).

CONCLUSIONS

The policy of offering mammographic screening substantially reduces breast cancer mortality and can do so in women younger than 50 years. Cancer 2016;122:1832–5. © 2016 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.

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