Gamma Knife Radiosurgery For Atypical And Anaplastic Meningiomas: Histopathological Predictors For Local Control Failure

Gyu Dong Kim1, Jin Wook Kim1, Sun Ha Paek1, Hyun-Tai Chung, PhD2, Yong Hwy Kim1, Jung Ho Han3, Chae Yong Kim1

1Seoul National University Hospital, Seoul, Republic of Korea 2Seoul National University College of Medicine 3Gyeonggi-Do, Korea, Republic Of

Keywords: meningioma, outcome, malignant meningioma, gamma knife, recurrent disease

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     The authors retrospectively investigated the clinical outcomes of Gamma Knife radiosurgery (GKRS) for atypical meningiomas and anapalstic meningiomas
     Between 1998 and 2008, 23 patients with 34 lesions were treated with GKRS for atypical and anaplastic meningiomas which were pathologically re-evaluated with WHO 2007 classification.
     Median marginal dose was 17 Gy (range, 12-21 Gy)at the 50% ± 5% isodose line. Mean tumor volume was 3.65 cm3 (range, 0.03-25.3 cm3)
     Overall survival rates were 100% at 1 year, 86.7% at 2 years, 65% at 5 years. Actuarial local tumor control rates were 80% at 1 year, 50.0% at 2 years, and 27.2 % at 3 years. There were no adverse radiation effects. By multivariate analysis, only mitotic count (= 10) and MIB-1 lable index ( = 10) were significant prognostic factors of local tumor control failure. (p= 0.013, HR= 42.273, 95% confidence interval 2.23-801.46, p=0.030 HR=12.415 95% CI 1.284-120.01, respectively).
     This is a retrospective study.
     Gamma Knife radiosurgery for atypical meningiomas was safe and effective modalities. But, more aggressive treatments were needed for anaplastic meningiomas.
     Also, the tumor factor such as mitotic count ( = 10) and MIB-1 lable index ( = 10%) must be considered before GKRS.


Project Roles:

G. Kim (), J. Kim (), S. Paek (), H. Chung (), Y. Kim (), J. Han (), C. Kim ()