Population estimates of survival in women with screen-detected and symptomatic breast cancer taking account of lead time and length bias
- 12 July 2008
- journal article
- research article
- Published by Springer Science and Business Media LLC in Breast Cancer Research and Treatment
- Vol. 116 (1), 179-185
- https://doi.org/10.1007/s10549-008-0100-8
Abstract
Background Evidence of the impact of breast screening is limited by biases inherent in non-randomised studies and often by lack of complete population data. We address this by estimating the effect of screen detection on cause-specific fatality in breast cancer, corrected for all potential biases, using population cancer registry data. Methods Subjects (N = 26,766) comprised all breast cancers notified to the West Midlands Cancer Intelligence Unit and diagnosed in women aged 50–74, from 1988 to 2004. These included 10,100 screen-detected and 15,862 symptomatic breast cancers (6,009 women with interval cancers and 9,853 who had not attended screening). Our endpoint was survival to death from breast cancer. We estimated the relative risk (RR) of 10-year cause-specific fatality (screen-detected compared to symptomatic cancers) correcting for lead time bias and performing sensitivity analyses for length bias. To exclude self-selection bias, survival analyses were also performed with interval cancers as the comparator symptomatic women. Findings Uncorrected RR associated with screen-detection was 0.34 (95% CI 0.31–0.37). Correcting for lead time, RR was 0.49 (95% CI 0.45–0.53); length bias analyses gave a range of RR corrected for both phenomena of 0.49–0.59, with a median of 0.51. Self-selection bias-corrected estimates yielded a median RR of 0.68. Interpretation After adjusting for various potential biases, women with screen-detected breast cancer have a substantial survival advantage over those with symptomatic breast cancer.Keywords
This publication has 13 references indexed in Scilit:
- Correcting for Lead Time and Length Bias in Estimating the Effect of Screen Detection on Cancer SurvivalAmerican Journal of Epidemiology, 2008
- Population screening and intensity of screening are associated with reduced breast cancer mortality: evidence of efficacy of mammography screening in AustraliaBreast Cancer Research and Treatment, 2007
- Overdiagnosis, Sojourn Time, and Sensitivity in the Copenhagen Mammography Screening ProgramThe Breast Journal, 2006
- A 13-year follow-up of patients with breast cancer presenting to a District General Hospital breast unit in southeast EnglandThe Breast, 2006
- Rate of over-diagnosis of breast cancer 15 years after end of Malmö mammographic screening trial: follow-up studyBMJ, 2006
- Overdiagnosis and overtreatment of breast cancer: Estimates of overdiagnosis from two trials of mammographic screening for breast cancerBreast Cancer Research, 2005
- Evaluation of service screening mammography in practice: the impact on breast cancer mortalityAnnals of Oncology, 2005
- A case-control study to estimate the impact on breast cancer death of the breast screening programme in WalesJournal of Medical Screening, 2004
- THE SWEDISH TWO-COUNTY TRIAL TWENTY YEARS LATER: Updated Mortality Results and New Insights from Long-Term Follow-upRadiologic Clinics of North America, 2000
- Breast screening, prognostic factors and survival – results from the Swedish two county studyBritish Journal of Cancer, 1991