Factors Related with Local Tumor Control after Gamma Knife Radiosurgery for Intracranial Meningiomas

Kim, Ho Sang; Lee, Jung Hwan; Choi, Chang Hwa; Hur, Byeon Ik; Cho, Won Ho; Cha, Seung Heon

Original article

Journal of the Korean Society of Stereotactic and Functional Neurosurgery 2009;5(2):82-85.
Published online September 30, 2009.

Factors Related with Local Tumor Control after Gamma Knife Radiosurgery for Intracranial Meningiomas

Ho Sang Kim, Jung Hwan Lee, Chang Hwa Choi, Byeon Ik Hur, Won Ho Cho, Seung Heon Cha

Department of Neurosurgery, School of Medicine, Pusan National University, Busan, Korea

Abstract

Objective
Over the past two decades, gamma knife radiosurgery (GKS) has emerged as alternative to microsurgery and adjuvant treatment after surgical resection. In this study, we made retrospective analysis to examine the outcome and the factor affecting tumor control in patients with meningioma treated using GKS. Materials and Methods: From October 2003 to October 2006, 53 patients with intracranial meningiomas were treated with GKS. Complete follow-up was available in the 40 patients (23 women and 17 men). Serial magnetic resonance images were performed to assess tumor response. Radiologic responses were categorized as decreased, not-changed and enlarged group. Tumor control group was defined a decreased and not-changed group. Fisher's exact test was used to evaluate statistical analysis.
Results
The Overall tumor control rate was 87.5%. The tumor control rate was related with tumor volume (TV) and histological type. Tumor control rate was 100% in group of TV<4.0cc, compared with 76.2% in group of TV>4.0cc. Patients with WHO grade I meningioma exhibited a tumor control rate of 100%, compared with 33.3% in patients with WHO grade II menignioma. Sex, tumor location and radiation dose were not associated with tumor control rate.
Conclusion
GKS for the treatment of meningiomas showed excellent results in the present study. The small and WHO I grade meningiomas exhibit more effective results in GKS and even though in WHO grade II, small-sized meningiomas showed favorable tumor control rate. Histologic grade and tumor volume were correlated with tumor control rate.

Key Words: Gamma knife radiosurgery, Meningioma, Tumor control rate.