Long-term experience with World Health Organization grade III (malignant) meningiomas at a single institution

To evaluate the outcomes for patients with Grade III meningiomas as defined by the 2007 World Health Organization standards.

The slides from patients who had been treated at the Cleveland Clinic for malignant meningiomas were reviewed by a single neuropathologist. The data from 13 patients treated between 1984 and 2006 satisfied the World Health Organization 2007 definition of Grade III meningioma. A total of 24 surgeries were performed, including 13 primary, 7 salvage, and 4 second salvage. Also, 14 courses of radiotherapy (RT) were administered, including fractionated RT in 3 patients after primary surgery, fractionated RT in 4 patients after salvage surgery, salvage stereotactic radiosurgery to six separate areas in 3 patients, and salvage intensity-modulated RT in 1 patient.

From the primary surgery, the median survival was 3.4 years, the 5-year survival rate was 47.2%, and the 8-year survival rate was 12.2%. The median time to recurrence was 9.6 months. A trend was seen toward longer survival for patients who had received adjuvant RT after initial surgery compared with those treated with surgery alone. Two patients developed radiation necrosis, and three had surgical complications.

This is one of the few studies reporting the outcomes for malignant meningioma patients according to recent definitions. Our results are consistent with existing reports of the overall poor outcomes for atypical and malignant meningioma patients. From the available data, surgical resection followed by RT and salvage therapy can lead to extended survival.