Incidence Rates and Surgery of Primary Intraspinal Tumors in the Era of Modern Neuroimaging A National Population-Based Study

Study Design. Prospective national population-based cohort study. Objective. To evaluate national population-based data on histopathologically verified intraspinal tumors and explore time trends in incidence and surgery rates and associations with the increased availability of magnetic resonance imaging (MRI) during 1993 and 2011. Summary of Background Data. There is a relative lack of updated epidemiological data on primary intraspinal tumors and most previous studies do not capture the advances in diagnostics and surgical treatment in the era of modern neuroimaging. The possible effect of the increasing availability of MRI on incidence rates and clinical management of primary intraspinal tumors is not known. Methods. We included all patients with a histologically verified intraspinal tumor diagnosed between 1993 and 2011 in a population-based cohort based on data from the Cancer Registry of Norway. The incidence and surgery rates were calculated and compared with the number of available MRI scanners in Norway. Results. We identified 1104 patients diagnosed with a primary intraspinal tumor. The incidence rate based on the Norwegian population between 1993 and 2011 was 1.28 per 100,000. In 1993, there were 8 MRI scanners in Norway increasing to 125 in 2011. There seems to be a plateau in the increase in incidence rates after 2002 where the subsequent increase in the number of MRI scanners did not seem to be followed by further increases of intraspinal tumor surgery. Conclusion. The incidence rate of primary intraspinal tumors in Norway changed dramatically during the study period, stabilizing around 1.5 per 100,000 per year since 2002. There was an increase in surgery for all major subgroups. This increase in surgical activity seems to correlate with the simultaneous large increase in the availability of diagnostic magnetic resonance imaging.