Dose-Response Relationships for Meningioma Radiosurgery

Area of Science:

• Neurosurgery
• Radiation Oncology
• Oncology

Background:

• Dose-response relationships for meningioma radiosurgery are not well understood.
• Optimizing tumor control requires understanding factors influencing local recurrence.

Purpose of the Study:

• To evaluate determinants of local recurrence in meningiomas treated with Gamma Knife radiosurgery (GKRS).
• To guide future treatment strategies for improved meningioma tumor control.

Main Methods:

• A retrospective study of 101 patients (108 tumors) treated with GKRS for benign, atypical, or malignant meningiomas (1998-2011).
• Local recurrence was assessed using Cox proportional hazards and logistic regression analyses.
• Patient, tumor, and treatment characteristics were analyzed for association with local recurrence; toxicity was also evaluated.

Main Results:

• Tumor grades were I (82%), II (11%), and III (7%).
• Two-/five-year local control rates were 100%/98% for grade I and 76%/56% for grades II/III.
• Higher tumor grade and lower GKRS dose were linked to local failure; each 1 Gy dose increase reduced recurrence by 42%.

Conclusions:

• GKRS treatment was well-tolerated with no severe toxicity.
• Tumor control was excellent for benign meningiomas but suboptimal for higher-grade tumors.
• Dose escalation to 16-20 Gy is recommended for atypical/malignant tumors to improve local control, provided critical structures are spared.