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Evaluating mammography screening in observational cohort designs: the importance of avoiding lead time bias.

Authors :
RØssell EL
Lousdal ML
Viuff JH
StØvring H
Source :
Scandinavian journal of public health [Scand J Public Health] 2024 Oct 27, pp. 14034948241288136. Date of Electronic Publication: 2024 Oct 27.
Publication Year :
2024
Publisher :
Ahead of Print

Abstract

Aims: To investigate the potential lead time bias of the evaluation model (extended follow-up for women diagnosed with breast cancer) used to evaluate mammography screening in a recent Danish study. This model was compared with two traditional models.<br />Methods: We retrieved data on women diagnosed with breast cancer in each county of Norway from 1986 to 2016. In a population-based open cohort study, the change in incidence-based mortality (IBM) was estimated by relative rate ratios comparing a screening period with a historical period for each of three age groups: women eligible for screening and younger and older ineligible women. We applied the evaluation model, and for comparison two traditional IBM models from a recent Norwegian study: one without extended follow-up and no possibility of lead time bias and one with extended follow-up irrespective of diagnosis, possibly diluting any screening effect.<br />Results: The evaluation model estimated an extra 11% reduction in breast cancer mortality among the screening eligible relative to ineligible women. However, this result could largely be ascribed to lead time bias inflated by overdiagnosis and a decreasing mortality from other causes among eligible women. A reduction in breast cancer mortality was observed for both eligible and younger and older ineligible women across models, and relative rate ratios close to 1 were obtained using the two traditional IBM models, indicating no effect of screening on breast cancer mortality.<br />Conclusions: Two models without lead time bias found no reduction in breast cancer mortality, whereas the evaluation model estimated a reduction attributable to lead time bias .<br />Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Details

Language :
English
ISSN :
1651-1905
Database :
MEDLINE
Journal :
Scandinavian journal of public health
Publication Type :
Academic Journal
Accession number :
39462832
Full Text :
https://doi.org/10.1177/14034948241288136