Is the incidence of brain tumors really increasing? A population-based analysis from a cancer registry.

Recently, an increasing incidence of brain tumors has been reported from multiple studies. Brain tumors diagnosed in the period 1985-2005 were identified through the Tuscan Cancer Registry, a population-based registry active since 1985 in the area of Florence and Prato. Age-standardized incidence rates and average annual percent change (APC) was calculated for the entire period from 1985 to 2005 for sex and behavior. A total of 4,417 brain tumors was registered, 1,900 (43%) in male and 2,517 (57%) in female patients. Malignant and benign tumor incidence rates were 8.3 and 4.1, respectively, among males and 6.4 and 7.2, respectively, among females. The age-adjusted annual incidence rate of all brain tumors was 13.9, with a statistically significant increasing rate throughout the period (APC: +3.2, CI 2.2-4.2). The annual incidence rate remained stable for malignant brain tumors but increased significantly for benign brain tumors (APC: +6.2, CI 4.5-7.9). In our population-based study, the incidence of brain tumors increased from 1985 to 2005 overall and for benign tumors, but not for malignant tumors. Part of the temporal variations may be attributed to improvement in diagnostic imaging techniques and, particularly for benign tumors, in changes in registration practice.