Use of population-based cancer registry data to evaluate organized breast cancer screening programmes in Europe by mode of detection: a scoping review.

Organized breast cancer screening programmes are a cornerstone of cancer control policy across Europe. Population-based cancer registries (PBCRs) play a central role in monitoring screening performance, outcomes, and programme quality. However, the extent and methodological approaches of registry-based evaluations across Europe have not been comprehensively synthesized. Following PRISMA-ScR guidelines, we conducted a scoping review of peer-reviewed studies evaluating organized breast cancer screening programmes in Europe using PBCR data. Studies were identified through systematic database searches and screened using predefined eligibility criteria. Data were extracted on study design, definitions of detection mode, outcome measures, and approaches to bias adjustment. The Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework guided the methodological analysis. Twenty-six studies were included, mainly from Western and Northern Europe, with most published before 2010. Screen-detected cancers consistently showed lower mortality, better survival, and more favourable tumour characteristics than interval or non-screened cancers. However, reporting of screening indicators was inconsistent. Definitions of detection modes, particularly interval cancers, and approaches to bias adjustment varied widely, limiting comparability. Few studies applied comprehensive bias correction or clearly reported registry-screening data linkage. Registry-based evaluations provide valuable evidence on the impact of breast cancer screening programmes, However, the evidence is limited by methodological heterogeneity and limited analytical standardization, reducing its comparability and policy relevance. Strengthening standardized definitions, improving transparency in analytical approaches, and better integrating programme monitoring with research could enhance the public health value of registry-based screening evaluation.