All authors are employed at the Cancer Registry of Norway, which administers the Norwegian Breast Cancer Screening Program. All data used in this study were available for all authors of the study.
Breast cancer mortality in participants of the Norwegian Breast Cancer Screening Program
Article first published online: 29 MAY 2013
Copyright © 2013 American Cancer Society
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Volume 119, Issue 17, pages 3106–3112, 1 September 2013
How to Cite
Hofvind, S., Ursin, G., Tretli, S., Sebuødegård, S. and Møller, B. (2013), Breast cancer mortality in participants of the Norwegian Breast Cancer Screening Program. Cancer, 119: 3106–3112. doi: 10.1002/cncr.28174
- Issue published online: 20 AUG 2013
- Article first published online: 29 MAY 2013
- Manuscript Accepted: 17 APR 2013
- Manuscript Revised: 12 APR 2013
- Manuscript Received: 29 JAN 2013
- mass screening;
- breast neoplasms/mortality;
- breast neoplasms/prevention and control;
- breast neoplasms/radiography;
The Norwegian Breast Cancer Screening Program started in 1996. To the authors' knowledge, this is the first report using individual-based data on invitation and participation to analyze breast cancer mortality among screened and nonscreened women in the program.
Information on dates of invitation, attendance, breast cancer diagnosis, emigration, death, and cause of death was linked by using unique 11-digit personal identification numbers assigned all inhabitants of Norway at birth or immigration. In total, 699,628 women ages 50 to 69 years without prior a diagnosis of breast cancer were invited to the program from 1996 to 2009 and were followed for breast cancer through 2009 and death through 2010. Incidence-based breast cancer mortality rate ratios (MRRs) were compared between the screened and nonscreened cohorts using a Poisson regression model. The MRRs were adjusted for calendar period, attained age, years since inclusion in the cohorts, and self-selection bias.
The crude breast cancer mortality rate was 20.7 per 100,000 women-years for the screened cohort compared with 39.7 per 100,000 women-years for the nonscreened cohort, resulting in an MRR of 0.52 (95% confidence interval, 0.47-0.59). The mortality reduction associated with attendance in the program was 43% (MRR, 0.57; 95% confidence interval, 0.51-0.64) after adjusting for calendar period, attained age, years after inclusion in the cohort, and self-selection bias.
After 15 years of follow-up, a 43% reduction in mortality was observed among women who attended the national mammographic screening program in Norway. Cancer 2013;119:3106–3112. © 2013 American Cancer Society.