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dc.date.accessioned2017-12-20T16:04:50Z
dc.date.available2017-12-20T16:04:50Z
dc.date.created2017-11-24T16:19:24Z
dc.date.issued2017
dc.identifier.urihttp://hdl.handle.net/10852/59397
dc.description.abstractMammographic density represents the amount of the epithelium and fibrous tissue in the breast and refers to the radiographic density of the breast visible on mammography. The epithelium and fibrous tissues are radiodense, and appear as white or light gray areas on a mammogram, whereas the fatty tissue is radiolucent, and appears as black or dark gray areas. Mammographic density has been shown to be an independent risk factor for breast cancer. Women with high density (>75% dense tissue) have a four- to six-fold increased risk of breast cancer compared to women with entirely fatty breasts (<25% dense tissue). High mammographic density also significantly decreases the sensitivity of mammography. Furthermore, dense breasts can negatively influence early performance measures of a screening program, resulting in a higher recall rate, missed tumors due to masking and an increased risk of interval cancer. In this thesis, I examined the role of mammographic density in breast cancer screening in Norway. The goal was to contribute with knowledge that would be helpful in determining whether mammographic density could be used for future stratified screening. The articles in this thesis are based on information about women screened in the Norwegian Breast Cancer Screening Program. We investigated whether mammographic density affects early performance measures of breast cancer screening, which compression parameters are associated with density estimates, and how different mammographic density classifications correspond to each other. Mammographic density was assessed both subjectively, by breast radiologists working in the screening program, and objectively, using a fully automated method. We found that positive predictive values for recall examinations and invasive procedures decreased with increasing mammographic density among women screened in the program. We also determined that high mammographic density was associated with large (>15 mm) tumor size and positive lymph node status in women with screen-detected invasive breast cancer. Further, we identified correlations between compression force, pressure, compressed breast thickness, breast volume and fibroglandular volume, and volumetric breast density. The strongest associations were observed between compression pressure, breast volume and fibroglandular volume, and between compressed breast thickness and volumetric breast density. We found that subjective mammographic density classifications used by the screening program in Norway corresponded well to estimates of the fully automated density assessment method. The results of our studies indicated that mammographic density could be a useful tool in stratification of breast cancer screening. However, the obtained evidence is currently not sufficient to support stratified screening for breast cancer based on mammographic density in Norway.en_US
dc.languageEN
dc.language.isoenen_US
dc.publisherUniversity of Oslo, Faculty of Medicine
dc.relation.haspartPaper I Moshina N, Ursin G, Roman M, Sebuødegård S, Hofvind S. Positive predictive values by mammographic density and screening mode in the Norwegian Breast Cancer Screening Program. Eur J Radiol 2016; 85(1):248-54. The paper is not available in DUO due to publisher restrictions. The published version is available at: https://doi.org/10.1016/j.ejrad.2015.11.030
dc.relation.haspartPaper II Moshina N, Ursin G, Hoff SR, Akslen LA, Roman M, Sebuødegård S, Hofvind S. Mammographic density and histopathologic characteristics of screen-detected tumors in the Norwegian Breast Cancer Screening Program. Acta Radiol Open 2015; 4(9) 50. The paper is available in DUO: http://hdl.handle.net/10852/48493
dc.relation.haspartPaper III Moshina N, Roman M, Waade GG, Sebuødegård S, Ursin G, Hofvind S. Breast compression parameters and mammographic density in the Norwegian Breast Cancer Screening Program. Eur Radiol. 2017 Nov 2. doi: 10.1007/s00330-017-5104-5. [Epub ahead of print] Author version available in DUO: http://hdl.handle.net/10852/59396
dc.relation.haspartPaper IV Moshina N, Roman M, Sebuødegård S, Waade GG, Ursin G, Hofvind S. Comparison of subjective and fully automated methods for measuring mammographic density. Acta Radiol. 2017 Jan 1:284185117712540. doi: 10.1177/0284185117712540. [Epub ahead of print] The paper is not available in DUO due to publisher restrictions. The published version is available at: https://doi.org/10.1177/0284185117712540
dc.relation.urihttps://doi.org/10.1016/j.ejrad.2015.11.030
dc.relation.urihttp://hdl.handle.net/10852/48493
dc.relation.urihttp://hdl.handle.net/10852/59396
dc.relation.urihttps://doi.org/10.1177/0284185117712540
dc.titleUnderstanding the role of mammographic density in a population based breast cancer screening program: A step towards stratified screening for breast cancer in Norway?en_US
dc.typeDoctoral thesisen_US
dc.creator.authorMoshina, Nataliia
cristin.unitcode185,50,0,0
cristin.unitnameDet medisinske fakultet
cristin.ispublishedtrue
cristin.fulltextoriginal
dc.identifier.cristin1518264
dc.identifier.pagecount130
dc.identifier.urnURN:NBN:no-62080
dc.type.documentDoktoravhandlingen_US
dc.source.isbn978-82-8377-109-1
dc.identifier.fulltextFulltext https://www.duo.uio.no/bitstream/handle/10852/59397/4/PhD-Moshina-DUO.pdf


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