Data Quality at the Cancer Registry of Norway: an Overview of Comparability, Completeness, Validity and Timeliness

Aim: To provide a comprehensive evaluation of the quality of the data collected on both solid and non-solid tumours at the Cancer Registry of Norway (CRN).

Methods: Established quantitative and semi-quantitative methods were used to assess comparability, completeness, accuracy and timeliness of data for the period 1953-2005, with special attention to the registration period 2001-2005.

Results: The CRN coding and classification system by and large follows international standards, with some further subdivisions of morphology groupings performed in-house. The overall completeness was estimated at 98.8% for the registration period 2001-2005. There remains a variable degree of under-reporting particularly for haematological malignancies (C90-95) and tumours of the central nervous system (C70-72). For the same period, 93.8% of the cases were morphologically verified (site-specific range: 60.0-99.8%). The under-reporting in 2005 due to timely publication is estimated at 2.2% overall, based on the number of cases received at the registry during the following year.

Conclusion: This review suggests the routines in place at the CRN yields comparable data that can be considered reasonably accurate, close-to-complete and timely, thereby justifying our policy of the reporting of annual incidence one year after the year of diagnosis.