Seemingly complete removal of histologically benign intracranial meningioma: late recurrence rate and factors predicting recurrence in 657 patients. A multivariate analysis.

From 1953 to 1980, 657 patients survived a seemingly complete removal of a histologically benign intracranial meningioma. Recurrence of the tumor was found in 59 of these 657 patients, but some cases of recurrence may have been missed inasmuch as only 69 patients were followed for 20 years. With ordinary life-table analysis, the overall recurrence rate was estimated to be 19% at 20 years. The reliability of this result was evaluated with a modified life-table analysis. Multivariate analysis showed that coagulation of the dural insertion, invasion of bone, and soft consistency of tumor were strong risk factors (p less than 0.01) for recurrence. The recurrence rate at 20 years was estimated to be 11% for the 249 patients with none of these risk factors, 15-24% for those with one factor, and 34-56% for those with two.