Background: Descriptive epidemiology of cerebral gliomas has recently been the subject of several studies, indicating a possible increase in brain tumor rates, particularly in the elderly population.
Methods: Between 1983 and 1990, 1376 registered patients with diagnoses of malignant astrocytomas, low grade astrocytomas, oligodendrogliomas - mixed oligoastrocytomas, and tumors without histologic confirmation were reviewed in 6 French cancer registries. The incidence rates by histologic type, age, and gender were calculated. The variation of the incidence between 1983 and 1990 was also analyzed.
Results: The highest incidence was observed in the malignant astrocytoma group (2.38/100,000/year) followed by the low grade astrocytoma group (0.54/100,000/year) and the oligodendroglioma - mixed oligoastrocytoma group (0.25/100,000/year). A significant male predominance was observed in the malignant astrocytoma group (male/female [M/F] ratio of 1.59; P < 0.001) and in the group without histologic confirmation (M/F ratio of 2.6; P = 0.008). Between 1983 and 1990, an increasing trend of 5% per year was observed in the incidence of malignant astrocytomas in the population older than 65 years.
Conclusions: These data confirm the observation made in other countries that the incidence of primary brain tumors (particularly malignant astrocytomas) is increasing in elderly patients.