Recurrence of intracranial meningiomas: did better methods of diagnosis and surgical treatment change the outcome in the last 30 years?

OBJECTIVE: Meningiomas are benign intracranial tumors growing from the arachnoid cap cells. Although their behavior is usually benign, they tend to recur even after total removal, and their recurrence is dependent on different aspects.

METHODS: Between 1991 and 2002, 463 patients with an intracranial meningioma were operated in the Department of Neurosurgery, University of Kiel, Kiel, Germany. We compared the outcome of these patients after operation and the different methods of radiation therapy and chemotherapy with the data from Buhl (1994), who analysed 661 patients with intracranial meningioma who were operated on in the Department of Neurosurgery, University of Essen, Essen, Germany, between 1968 and 1988, to find out whether better methods of diagnosis like magnetic resonance imaging scans, magnetic resonance spectroscopy, post-operative radiation therapy and chemotherapy have an influence on the recurrence and outcome after surgical treatment.

RESULTS: The patients' mean age in both studies was between 50 and 59 years. Both studies underlined the preponderance of female patients for intracranial meningiomas. In the primary study, there were 506 female and 208 male patients, and in the new study, there were 366 female and 97 male patients. The gender distribution changed from 2.4 : 1 to 3.8 : 1. Complete removal of the tumor was possible in 86.7% in both studies. The recurrence rate in the first study was 11% (73/661), while it was 16% in the second study (73/463). The intracranial localization of the meningiomas was similar to the distribution of the histological subtypes and the rate of recurrence; only the malignant meningiomas showed a higher grade of recurrence in the last study. Indications for post-operative radiation therapy were given earlier in the last study owing to the experience from the primary study. The outcome of the patients after surgical removal was improving in the last years; the 30 day post-operative mortality after a primary operation on an intracranial meningioma decreased from 12.1 to 3%. After removal of a recurrent meningioma, the mortality declined from 20 to 12.5%.

CONCLUSION: In the last 30 years, nothing important changed at the time of appearance of meningiomas, concerning the gender distribution and localisation as well as histological subtypes. With better operating modalities and additional treatment with radiation and gamma knife, the mortality decreased significantly from 12 to 3% and the outcome of the patients is still improving, so that even elderly patients with intracranial meningioma can undergo surgical treatment with minor risks.