title: Sorting out measures and definitions of screening participation to improve comparability: the example of colorectal cancer.
abstract: Participation is a key indicator of the potential effectiveness of any population-based intervention. Defining, measuring and reporting participation in cancer screening programmes has become more heterogeneous as the number and diversity of interventions have increased, and the purposes of this benchmarking parameter have broadened. This study, centred on colorectal cancer, addresses current issues that affect the increasingly complex task of comparing screening participation across settings. Reports from programmes with a defined target population and active invitation scheme, published between 2005 and 2012, were reviewed. Differences in defining and measuring participation were identified and quantified, and participation indicators were grouped by aims of measure and temporal dimensions. We found that consistent terminology, clear and complete reporting of participation definition and systematic documentation of coverage by invitation were lacking. Further, adherence to definitions proposed in the 2010 European Guidelines for Quality Assurance in Colorectal Cancer Screening was suboptimal. Ineligible individuals represented 1% to 15% of invitations, and variable criteria for ineligibility yielded differences in participation estimates that could obscure the interpretation of colorectal cancer screening participation internationally. Excluding ineligible individuals from the reference population enhances comparability of participation measures. Standardised measures of cumulative participation to compare screening protocols with different intervals and inclusion of time since invitation in definitions are urgently needed to improve international comparability of colorectal cancer screening participation. Recommendations to improve comparability of participation indicators in cancer screening interventions are made.
authors.affiliation: Cancer Epidemiology Unit, University Institute of Social and Preventive Medicine, Lausanne, Switzerland. Electronic address: Jean-Luc.Bulliard@chuv.ch.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Bulliard
authors.affiliation: Cancer Prevention and Control Program, IDIBELL, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain.
authors.forename: Montse
authors.initials: M
authors.lastname: Garcia
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Johannes
authors.initials: J
authors.lastname: Blom
authors.affiliation: AO Città della Salute e della Scienza, CPO Piemonte, Turin, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Senore
authors.affiliation: Canadian Partnership Against Cancer, Toronto, Canada.
authors.forename: Verna
authors.initials: V
authors.lastname: Mai
authors.affiliation: National Cancer Institute, Bethesda, MD, USA.
authors.forename: Carrie
authors.initials: C
authors.lastname: Klabunde
mesh_terms: D000328:Adult; D000368:Aged; D019985:Benchmarking / Q000379:methods*; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D055088:Early Detection of Cancer / Q000379:methods* / Q000592:standards; D005060:Europe; D019983:Guideline Adherence; D006801:Humans; D008403:Mass Screening / Q000379:methods* / Q000592:standards; D008875:Middle Aged; D017410:Practice Guidelines as Topic / Q000592:standards
keywords: Colorectal cancer; Definition; Participation; Programme; Screening