REGISTRATION QUALITY AND DESCRIPTIVE EPIDEMIOLOGY OF CHILDHOOD BRAIN-TUMORS IN SCOTLAND 1975-90

Children (0-14 years) with malignant brain and central nervous system (CNS) rumours (ICD9 191 and 192) were listed from the Scottish Cancer Registration Scheme for the years 1975-90. These cases formed the basi s for validation and verification procedures aimed at providing a comp lete and accurate data set for epidemiological analyses. A variety of data sources were cross-checked to optimise ascertainment, and resulti ng from this 5.7% of validated cases were found on the cancer registry with diagnostic codes outside the ICD-9 range 191-192. A further 8.4% were newly registered cases. Analyses were conducted on the validated data set showing a significant temporal increase in incidence rates o ver the 16 year study period with an average annual percentage change of + 2.6%. Large-scale geographical heterogeneity was also found, with a particularly high incidence in the Fife and Lothian areas and a low incidence in Grampian. Examination of associations with socioeconomic status, using the Carstairs deprivation index, revealed a rising tren d in incidence strongly linked to areas with increasing levels of affl uence. Our results suggest that for studies of childhood CNS tumours v alidation of cancer registry data is necessary and large-scale geograp hical variation and socioeconomic factors should be taken into account in any investigation of distribution in small geographical areas.