Primary brain tumour epidemiology in Georgia: first-year results of a population-based study.

A population-based cohort study was initiated in Georgia in March 2009 to collect epidemiologic data of malignant and non-malignant primary brain tumours. During the first year, 473 incident cases were identified. For a population of 4.3 million, the annual incidence rate was 10.25 per 100,000 inhabitants, age-standardized to the year 2000 US population. Non-malignant tumours constituted about 66 % of all tumours. Males accounted for 40 % and females for 60 % of the cases. Crude incidence rates by histology were highest for meningiomas (2.92/100,000), pituitary adenoma (1.16/100,000) and glioblastomas (0.64/100,000), which was in agreement with the frequency of reported histology: meningiomas--45.2 %, pituitary adenoma--18.0 % and glioblastomas--9.9 %. The age-standardized incidence rates were higher among females than males for all primary brain tumours (11.05 vs. 8.44/100,000) as well as for individual histologies except for glioblastoma and several other neuroepithelial tumours. Some differences compared with 2004-2005 Central Brain Tumor Registry of the United States data may be explained by a higher percentage of unclassified tumours (37 %) in our study. We suggest further studies to clarify the nature of this discrepancy.