Is Fractionated Gamma Knife Radiosurgery a Safe and Effective Treatment Approach for Large Volume >10 cm3) Intracranial Meningiomas?
BACKGROUND Even with great advances in surgery and improved clinical outcome, morbidity and mortality are still high for large volume intracranial meningiomas (MNGs) Recently, Gamma Knife radiosurgery (GKS) has proven to be a safe and effective treatment for many patients with intracranial MNGs. However, single session GKS may increase the risk of radiation induced toxicity for large MNGs. Recently, fractionated GKS (FGKS) has been performed for an increasing number of patients with surgically high risk and large intracranial tumors. In this study, we report our results on the efficacy and safety of FGKS for large MNGs. METHODS The authors performed a retrospective review of 70 patients who underwent GKS for large volume >10 cm3) intracranial MNGs between 2004 and 2015, with a minimum follow up of 12 months. The authors classified these patients into 2 groups of single session GKS, FGKS. The patients were followed by clinical examination and serial imaging with magnetic resonance imaging. RESULTS In the single session GKS group (42 patients) the median tumor volume was 15.2 cm3 (range 10.3 48.3 cm3) the median prescription dose was 12 Gy (range 8 14 Gy) and the median follow up duration was 57.8 months (range 14.5 128.4 months) In the FGKS group (28 patients) the median tumor volume was 21 cm3 (range 10.2 54.7 cm3) and the median prescription was 7.5 Gy in 2 fractions (range 5 8 Gy) 6 Gy in 3 fractions (range 5 6.5 Gy) and 4.5 Gy in 4 fractions. The median follow up duration for the FGKS group was 50 months (range 12.5 90.6 months) The overall 5 year tumor control rate was 92.9% in the FGKS group and 88.1% in the single session GKS group. Fourteen (33.3% symptomatic complications after single session GKS were noted, including 5 cases of hemiparesis, 4 of seizure, 3 of peritumoral edema, and 2 of hydrocephalus. Two (7.1% symptomatic complications after FGKS were noted, including 2 cases of hemiparesis. The FGKS group had higher progression free survival (PFS) rate at 5 years (92.9% vs. 88.1% but the differences did not reach statistical significance (P 0.389) The patients in the FGKS group, however, experienced a lower complication rate compared with patients with a single session GKS group (P 0.017, hazard ratio, 5.7:1) CONCLUSION When the large volume >10 cm3) intracranial MNGs are expected to have high morbidity after microsurgery and for patients that have a poor medical status for surgery, FGKS can be considered an alternative with good tumor control and lower complications rates compared with single session GKS (P 0.017)
World neurosurgery