Primary intracranial tumors. Survey of incidence in the province of Trento in the years 1977-1981.

The incidence rate of primary intracranial tumors in the Province of Trento from 1977 to 1981 was 7.4 per 100,000 inhabitants per year. The age curve is as reported by other authors, with two peaks, one early and the other, much higher, at 50-59 years. This curve reflects that of malignant tumors in males. The age-adjusted crude rate in males proved to be 7.4 (4.9 for malignant and 2.5 for benign tumors). The corresponding value in females was 7.4 (3.5 and 4.0). The most frequent tumors in males were astrocytomas, grades III and IV (M/F ratio = 1.6), and in females meningiomas (M/F ratio = 0.6). Hypophyseal adenomas, which accounted for 15.4% of all tumors, had an M/F ratio of 0.4. The factors likely to be responsible for the differences in incidence rates reported in the various surveys are discussed.