Nervous system tumors in adult immigrants to Sweden by subsite and histology.
ABSTRACT The coding of histology of nervous system (NS) tumors with various degrees of malignancies differs between cancer registries, whereby the comparison of incidence rates from one registry to another seems difficult. No study has systematically defined whether the change in the risk of NS tumors upon immigration in adulthood varies by subsite or histology. Therefore, we aimed to address this issue amongst the first-generation immigrants to Sweden based on a large uniform cancer registry data (1958-2006).
The nationwide Swedish Family-Cancer Database (2008 version; >11.8 million individuals; 1.8 million immigrants; histology code in force since 1958) was used to calculate standardized incidence ratios (SIRs). We analyzed 28,981 adult cases of NS tumors amongst Swedes and 2519 amongst immigrants (age ≥ 30).
Significantly decreased risks for brain glioma were amongst German (SIR = 0.64), Eastern European (0.62), some Asian (0.71), Chilean (0.34), and African immigrants (0.52). We found an increased risk for brain meningioma amongst Finns (1.15) and former Yugoslavians (1.33), whilst only Norwegians (0.71) and Latin Americans (0.21) had a decreased risk. The risk for spinal ependymoma and astrocytoma was increased in Germans (3.66) and former Yugoslavians (8.89). We found no significant difference for peripheral nerve tumors between immigrants and the native Swedes.
Significant differences between risk of NS tumors amongst immigrants and the native Swedes may suggest different risk factor profiles for glioma compared to meningioma indicating a higher etiological role of genetic background or childhood environmental risk factors rather than exposures after immigration.