Tumor Volume Shrinkage after SRT

• Main Authors: Engenhart-Cabillic, Rita, Henzel, Martin, Gross, M. W, Hamm, K., Surber, G., Kleinert, G., Strassmann, G.
• Format: Conference Proceeding
• Language: English
• ISSN: 1531-5010; 1532-0065
• DOI: 10.1055/s-2005-916557

Introduction: Fractionated stereotactic radiotherapy (SRT) is well established in the treatment of skull base meningiomas. Local tumor control is excellent (overall survival and the progression-free survival rates for 5 years: 92.9% and 96.9%, respectively). During follow-up 1/3 of the patients developed a radiological regression. We examined 94 patients prospectively in both departments to analyze quantitatively the tumor volume (TV) shrinkage. Material and Methods: Ninety-four patients (78 female, 16 male) suffering from a WHG I meningioma were examined under equal conditions (i.e., same technique and MRI scanner) before 6, 12, 18, and 24 months after SRT. Fat-saturated axial T1-weighted contrast-enhanced magnetic resonance imaging (MRI) scans with a 3-mm slice thickness were used. After image fusion TV was drawn in each slice for analyzing TV shrinkage three-dimensionally by the planning system. Results: Initially the mean TV was 13.4 mL (median: 8.5 mL). A decreasing mean TV shrinkage leading to a steady state was seen after SRT: 17.6% after 6 months (p