title: A novel method for identifying settings for well-motivated ecologic studies of cancer.
abstract: A low within-country variability and a large between-country variability in cancer incidence may indicate that ecologic factors are involved in the etiology of the disease. The aim of this study is to explore the within- and between-country variability of cancer incidence to motivate high-quality ecologic studies. We extracted age-standardized incidence rate estimates (world standard population) from 135 regions for the ten most frequent invasive cancers in Europe for non-Hispanic white populations from Cancer Incidence in Five Continents, Volume X. We fitted weighted multilevel Poisson regression models with random country effects for each cancer and sex. We estimated intraclass correlation coefficients (ICCs) and 95% confidence intervals (95% CIs). A high ICC indicates a low within- and a high between-country variability of rates. The two cancer sites with the highest ICC among men were prostate cancer (0.96, 95% CI: 0.92-0.99) and skin melanoma (0.78, 0.64-0.93). Among women, high ICCs were observed for lung cancer (0.84, 0.73-0.95) and breast cancer (0.80, 0.69-0.91). The two most prominent sex differences for ICC occurred for cancers of the head and neck (men: 0.70, 0.55-0.85, women: 0.19, 0.08-0.30) and breast cancer (men: 0.04, 0.01-0.07, women: 0.80, 0.69-0.91). ICCs were relatively low for pancreatic cancer (men: 0.23, 0.10-0.35; women: 0.13, 0.04-0.21) and leukemia (men: 0.12, 0.04-0.21; women: 0.08, 0.02-0.14). For cancers with high ICC for which systematic factors of the health care system, screening and diagnostic activities are not plausible explanations for between-country variations in incidence, cross-country sex-specific ecologic studies may be especially promising.
authors.affiliation: Center for Clinical Epidemiology, Institute of Medical Informatics, Biometry and Epidemiology, University Hospital of Essen, Essen, Germany.|School of Public Health, Department of Epidemiology, Boston University, Boston, MA.|German Consortium of Translational Cancer Research (DKTK), Heidelberg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Stang
authors.affiliation: Center for Clinical Epidemiology, Institute of Medical Informatics, Biometry and Epidemiology, University Hospital of Essen, Essen, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Kowall
authors.affiliation: Institute of Medical Epidemiology, Biometry and Informatics, Medical Faculty, Martin-Luther-University Halle-Wittenberg, Halle, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Rusner
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Britton
authors.initials: B
authors.lastname: Trabert
authors.affiliation: Section of Cancer Surveillance, International Agency for Research on Cancer, Lyon, France.
authors.forename: Freddie
authors.initials: F
authors.lastname: Bray
authors.affiliation: Section of Environment and Radiation, International Agency for Research on Cancer, Lyon, France.
authors.forename: Joachim
authors.initials: J
authors.lastname: Schüz
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: McGlynn
authors.affiliation: Centre for Health and Society, Faculty of Medicine, Heinrich Heine University, Düsseldorf, Germany.|Institute for Biometry and Epidemiology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Kuss
mesh_terms: D017753:Ecosystem; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology; D012042:Registries; D012107:Research Design
keywords: cancer registries; etiology; incidence; neoplasms