Data quality at the Cancer Registry of Norway: an overview of comparability, completeness, validity and timeliness.
OBJECTIVE
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.


CONCLUSIONS
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.
Larsen
Inger Kristin
IK
Department of Clinical and Registry-based Research, Cancer Registry of Norway, Institute of Population-based Cancer Research, Fridjof Nansens vei 19, Postbox 5313, Majorstuen, N-0304 Oslo, Norway. Electronic address: inger.kristin.larsen@kreftregisteret.no.
Småstuen
Milada
M
Department of Clinical and Registry-based Research, Cancer Registry of Norway, Institute of Population-based Cancer Research, Fridjof Nansens vei 19, Postbox 5313, Majorstuen, N-0304 Oslo, Norway.
Johannesen
Tom Børge
TB
Department of Clinical and Registry-based Research, Cancer Registry of Norway, Institute of Population-based Cancer Research, Fridjof Nansens vei 19, Postbox 5313, Majorstuen, N-0304 Oslo, Norway.
Langmark
Frøydis
F
Department of Clinical and Registry-based Research, Cancer Registry of Norway, Institute of Population-based Cancer Research, Fridjof Nansens vei 19, Postbox 5313, Majorstuen, N-0304 Oslo, Norway.
Parkin
Donald Maxwell
DM
Clinical Trials Service Unit and Epidemiological Studies Unit, University of Oxford, Oxford, UK; Cancer Research UK, Centre for Epidemiology, Mathematics and Statistics, London, UK.
Bray
Freddie
F
Department of Clinical and Registry-based Research, Cancer Registry of Norway, Institute of Population-based Cancer Research, Fridjof Nansens vei 19, Postbox 5313, Majorstuen, N-0304 Oslo, Norway; Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Norway.
Møller
Bjørn
B
Department of Clinical and Registry-based Research, Cancer Registry of Norway, Institute of Population-based Cancer Research, Fridjof Nansens vei 19, Postbox 5313, Majorstuen, N-0304 Oslo, Norway.
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000473:pathology*; D009664:Norway; D010338:Pathology, Clinical / Q000592:standards / Q000706:statistics & numerical data; D012042:Registries / Q000592:standards* / Q000706:statistics & numerical data; D012107:Research Design / Q000592:standards* / Q000706:statistics & numerical data; D055815:Young Adult