ABSTRACT
BACKGROUND: In Denmark, national roll-out of a population-based, screening mammography program took place in 2007-2010. We report on outcome of the first four biennial invitation rounds. METHODS: Data on screening outcome were retrieved from the 2015 and 2016 national screening quality reports. We calculated coverage by examination; participation after invitation; detection-, interval cancer- and false-positive rates; cancer characteristics; sensitivity and specificity, for Denmark and for the five regions. RESULTS: At the national level coverage by examination remained at 75-77%; lower in the Capital Region than in the rest of Denmrk. Detection rate was slightly below 1% at first screen, 0.6% at subsequent screens, and one region had some fluctuation over time. Ductal carcinoma in situ (DCIS) constituted 13-14% of screen-detected cancers. In subsequent rounds, 80% of screen-detected invasive cancers were node negative and 40% ≤10 mm. False-positive rate was around 2%; higher for North Denmark Region than for the rest of Denmark. Three out of 10 breast cancers in screened women were diagnosed as interval cancers. CONCLUSIONS: High coverage by examination and low interval cancer rate are required for screening to decrease breast cancer mortality. Two pioneer local screening programs starting in the 1990s were followed by a decrease in breast cancer mortality of 22-25%. Coverage by examination and interval cancer rate of the national program were on the favorable side of values from the pioneer programs. It appears that the implementation of a national screening program in Denmark has been successful, though regional variations need further evaluation to assure optimization of the program.
Subject(s)
Breast Neoplasms/diagnosis , Carcinoma, Ductal, Breast/diagnosis , Carcinoma, Intraductal, Noninfiltrating/diagnosis , Early Detection of Cancer/mortality , Mammography/mortality , Outcome Assessment, Health Care , Aged , Breast Neoplasms/epidemiology , Breast Neoplasms/mortality , Carcinoma, Ductal, Breast/epidemiology , Carcinoma, Ductal, Breast/mortality , Carcinoma, Intraductal, Noninfiltrating/epidemiology , Carcinoma, Intraductal, Noninfiltrating/mortality , Denmark/epidemiology , Female , Follow-Up Studies , Humans , Middle Aged , Prognosis , Survival RateABSTRACT
Mammography screening is offered healthy women, and a high standard on professional and organizational level is mandatory not only in the screening programme but even in the diagnostic work-up and treatment. The main goal is to achieve a substantial reduction in disease specific mortality, but it is not possible to evaluate the effect on mortality until several years later, and continuously monitoring of the quality of all aspects of a screening programme is necessary. Based on other European guidelines, 11 quality indicators have been defined, and guidelines concerning organizational requirements for a Danish screening programme as well as recommendations for the radiographic and radiological work have been drawn up.
