Treatment > Radiosurgery · Radiotherapy

Meeting Abstract

Is stereotactic radiotherapy adequate treatment for atypical and malignant meningiomas?

Simon S Lo, Kwan H Cho, Walter A Hall, Wilson L Hernandez, Kimberly K McCollow, Judy Unger

University of Minnesota, Minneapolis, MN

Method. From 1992 to 2000, 10 patients with 16 recurrent atypical (A) or malignant (M) meningiomas (5 A and 11 M) were treated with stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT). 
Patients with tumors greater than 4 cm or closer than 5 mm to the optic apparatus were chosen for FSRT. 
The SRS doses ranged from 1200 cGy at 50% to 4500 cGy at 50% and the FSRT doses ranged from 4500 cGy at 85% in 25 fractions to 5000 cGy at 90% in 20 fractions. 
A 2 mm margin was placed around the target as defined on the computerized tomography. 
The median follow-up ranged from 3 months to 66 months. 
Five patients had external beam radiation therapy to the same areas previously. 
All patients had radiologic follow-up with magnetic resonance imaging. 

Result. The 5-year actuarial tumor control was 31%. 
Five (50%) of the 10 patients developed recurrence. 
Two (40%) of the five patients who developed recurrence had disease recurring in the area outside the treated areas with no evidence of local recurrence. 
The time to recurrence ranged from 3 to 66 months. 
Three patients recurred after more than 3 years. 
The crude tumor shrinkage rate was 19%. 
The crude local progression rate was 31%. 

Conclusion. Our analysis showed that stereotactic therapy alone for the treatment of atypical and malignant meningiomas was associated with poor tumor control. 
The suboptimal local control and the propensity of A and M for regional recurrence warrant the investigation of more aggressive and innovative therapies. 
The potential long latency for tumor recurrence underscores the importance of long-term follow-up of these patients.

© Copyright 2002 American Society of Clinical Oncology