Epidemiology of primary intracranial tumours in NW Italy, a population based study: stable incidence in the last two decades.

Data about the epidemiology of primary intracranial tumours (PIT) are still heterogeneous depending on different methodological approach in collecting data. In Valle d' Aosta, north west side of Italy, we have carried out a prospective consecutive population based study to calculate the incidence of PIT in the last decade (1992-1999) and to compare these rates with the previous period (1986-1991), data reported in a previous paper. The mean annual PIT incidence rate (ri) per 100,000 inhabitants was 25.48. The mean annual incidence rates in the two period of comparison were adjusted to the 1991 Italian population by the direct method. The standardised ratio was 26.43 in the previous period and 23.24 in the second decade. There is no statistically significant difference. The mean annual PIT incidence rates by tumour types were meningiomas 13.27/100,000 (men 9.77; women 16.7), neuroepithelial group 9.3 (men 10.62; women 8.1), adenomas 1.26, neurinomas 0.7. Mean annual incidence rates by tumour class were also stable. The stable incidence rate in the two periods and the similar incidence in England (21.04/100,000 person year), strengthen the evidence for a stable incidence rate of PIT in the last decade. These three papers used similar methodology. The homogeneous methodology allows comparison and further evaluation.