Radiosurgery for atypical and anaplastic meningiomas: histopathological predictors of local tumor control.
OBJECTIVE
We investigated the radiosurgical outcomes of patients with nonbenign meningiomas retrospectively and sought to identify prognostic factors for local tumor control after radiosurgery with an emphasis on histopathology.


METHODS
Between 1998 and 2010, 35 patients with 49 atypical or anaplastic meningiomas were treated with radiosurgery. The mean tumor volume and marginal irradiation dose were 3.5 cm3 (range 0.3-25.3) and 16 Gy (range 12-21), respectively.


RESULTS
The actuarial local tumor control rates for patients with atypical meningiomas at 1, 2 and 3 years after radiosurgery were 78, 53 and 36%, respectively, whereas those for anaplastic meningiomas were 35% at 1 year and 10% at 2 years. Multivariate analysis revealed that the mitotic count (≤8 per 10 high-power fields; HPF) and the MIB-1 proliferation marker labeling index (LI; ≤8%) were significant favorable prognostic factors for the radiosurgical outcomes of patients with nonbenign meningiomas (p = 0.014 and p = 0.012, respectively).


CONCLUSIONS
Radiosurgery could be a treatment option for patients with atypical meningiomas, but more aggressive treatments are needed for those with anaplastic meningiomas. Histopathological factors such as mitotic count and MIB-1 LI are significant prognostic factors for the radiosurgical outcomes of patients with nonbenign meningiomas and should be considered before radiosurgery.
Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea.
Jin Wook
JW
Kim
Dong Gyu
DG
Kim
Sun Ha
SH
Paek
Hyun-Tai
HT
Chung
Jae Kyung
JK
Myung
Sung-Hye
SH
Park
Yong Hwy
YH
Kim
Jung Ho
JH
Han
Seung-Yeob
SY
Yang
Chul-Kee
CK
Park
Hee-Won
HW
Jung
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery*; D008579:Meningioma / Q000145:classification / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D011237:Predictive Value of Tests; D016634:Radiosurgery / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult