Factors affecting operative and excess long-term mortality in 935 patients with intracranial meningioma.

Between 1953 and 1980, a total of 935 patients underwent surgery for intracranial meningioma in the Department of Neurosurgery of the Helsinki University Hospital. The patients were followed up until death or the end of the year 1987. The cumulative observed survival rate was 91% at 3 months, 89% at 1 year, and 63% at 15 years. The relative survival rate, that is, the ratio of the the observed and the expected rates, was 91% at 3 months, 89% at 1 year, and 78% at 15 years. Significant risk factors for operative mortality (7%) for the 652 patients operated on from 1966 to 1980 were poor preoperative clinical condition, absence of epilepsy, old age, incomplete tumor removal, pulmonary embolism, and an intracranial hematoma requiring evacuation. For those 828 patients who survived the first postoperative year, the factors predicting an excess risk of death for up to 15 years were incomplete tumor removal, poor pre- and postoperative clinical condition, anaplasia of the tumor, and hyperostosis. Patients whose tumors were not completely removed had a 4.2-fold relative excess risk of death as compared with patients whose tumors were completely removed, and patients who had malignant tumors had a 4.6-fold risk as compared with those who had benign tumors.