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dc.contributor.authorLund, Eiliv
dc.contributor.authorNakamura, Aurelie
dc.contributor.authorThalabard, Jean-Christophe
dc.date.accessioned2019-05-14T13:13:55Z
dc.date.available2019-05-14T13:13:55Z
dc.date.issued2017-12-12
dc.description.abstract<i>Background</i>: The Norwegian Breast Cancer Screening Program (NBCSP) was implemented across the country in 2005 and has been criticised for potential ‘overdiagnosis’, i.e. a breast cancer diagnosis that otherwise would not have been detected or treated in a woman’s lifetime. We aimed to estimate overdiagnosis in the NBCSP based on the Norwegian Women and Cancer (NOWAC) study using both questionnaire information and record linkage information from NBCSP.<p> <p><i>Method</i>: For 124,978 women aged 49e79 years from the NOWAC study, information on <i>screened</i> women could be cross-validated from the NBCSP database. Based on information from the NOWAC questionnaire, <i>unscreened women</i> were further divided into those who had <i>mammograms taken only outside the NBCSP</i> and those who had <i>never had taken a mammogram</i>. Breast cancers diagnosed in 2005e2013 were identified through linkage to the Cancer Registry of Norway; in situ or DCIS 417; invasive 2845; combined 3262. Cumulative incidence rates (CIRs) for ages 49e79 years of breast cancer were compared using the log-rank test.<p> <p><i>Results</i>: After exclusion of women with a family history of breast cancer, screened women had a CIR of 9.7% for combined breast cancer, non-significantly lower compared with unscreened women. Screened women had a 1.1% increased CIR or 13.0% increased relative risk of breast cancer diagnosis (significant) compared with women who had never had a mammogram, but for invasive breast cancer alone the difference was reduced to -0.2% (95% CI: -9.1; 8.8). Invasive breast cancers were significantly smaller (<2.5 cm) in screened versus unscreened women. There was a borderline significant decrease in lymph node positive cancer among screened (p Z 0.06).<p> <p><i>Conclusion</i>: The findings of no significant overdiagnosis combined with smaller tumours and less lymph node metastases suggest that the prevailing view of overdiagnosis in the NBCSP should be challenged.<p>en_US
dc.descriptionSource at <a href=https://doi.org/10.1016/j.ejca.2017.11.003>https://doi.org/10.1016/j.ejca.2017.11.003. </a>en_US
dc.identifier.citationLund, E., Nakamura, A. & Thalabard, J-C. (2018). No overdiagnosis in the Norwegian Breast Cancer Screening Program estimated by combining record linkage and questionnaire information in the Norwegian Women and Cancer study. <i>European Journal of Cancer, 89</i>, 102-112. https://doi.org/10.1016/j.ejca.2017.11.003en_US
dc.identifier.cristinIDFRIDAID 1626576
dc.identifier.doi10.1016/j.ejca.2017.11.003
dc.identifier.issn0959-8049
dc.identifier.issn1879-0852
dc.identifier.urihttps://hdl.handle.net/10037/15304
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.relation.journalEuropean Journal of Cancer
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/MAMMOGRAFI/189505/Norway/Evaluation of the Norwegian Breast Cancer Screening Program//en_US
dc.rights.accessRightsopenAccessen_US
dc.subjectOverdiagnosisen_US
dc.subjectBreast canceren_US
dc.subjectThe Norwegian Breast Cancer Screening Programen_US
dc.subjectThe Norwegian Women and Cancer studyen_US
dc.subjectNOWACen_US
dc.subjectVDP::Medical disciplines: 700::Health sciences: 800::Community medicine, Social medicine: 801en_US
dc.subjectVDP::Medisinske Fag: 700::Helsefag: 800::Samfunnsmedisin, sosialmedisin: 801en_US
dc.titleNo overdiagnosis in the Norwegian Breast Cancer Screening Program estimated by combining record linkage and questionnaire information in the Norwegian Women and Cancer studyen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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