Comparing interval breast cancer rates in Norway and North Carolina: results and challenges.

TitleComparing interval breast cancer rates in Norway and North Carolina: results and challenges.
Publication TypeJournal Article
Year of Publication2009
AuthorsHofvind, S, Yankaskas, BC, Bulliard, J-L, Klabunde, CN, Fracheboud, J
JournalJ Med Screen
Date Published2009
KeywordsAged, Breast Neoplasms, Female, Humans, Mass Screening, Middle Aged, North Carolina, Norway

OBJECTIVE: To compare interval breast cancer rates (ICR) between a biennial organized screening programme in Norway and annual opportunistic screening in North Carolina (NC) for different conceptualizations of interval cancer.

SETTING: Two regions with different screening practices and performance.

METHODS: 620,145 subsequent screens (1996-2002) performed in women aged 50-69 and 1280 interval cancers were analysed. Various definitions and quantification methods for interval cancers were compared.

RESULTS: ICR for one year follow-up were lower in Norway compared with NC both when the rate was based on all screens (0.54 versus 1.29 per 1000 screens), negative final assessments (0.54 versus 1.29 per 1000 screens), and negative screening assessments (0.53 versus 1.28 per 1000 screens). The rate of ductal carcinoma in situ was significantly lower in Norway than in NC for cases diagnosed in both the first and second year after screening. The distributions of histopathological tumour size and lymph node involvement in invasive cases did not differ between the two regions for interval cancers diagnosed during the first year after screening. In contrast, in the second year after screening, tumour characteristics remained stable in Norway but became prognostically more favorable in NC.

CONCLUSION: Even when applying a common set of definitions of interval cancer, the ICR was lower in Norway than in NC. Different definitions of interval cancer did not influence the ICR within Norway or NC. Organization of screening and screening performance might be major contributors to the differences in ICR between Norway and NC.

Alternate URL

Alternate JournalJ Med Screen
Citation Key / SERVAL ID2817
PubMed ID19805754
Grant ListNC U58 DP000123-02 / DP / NCCDPHP CDC HHS / United States
U01-CA70040 / CA / NCI NIH HHS / United States


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