Low-dose radiosurgery for benign intracranial lesions

Area of Science:

• Neurosurgery
• Radiation Oncology
• Medical Physics

Background:

• Benign intracranial tumors require effective treatment with minimal side effects.
• Radiosurgery offers a non-invasive option for managing these lesions.
• Optimizing radiation dosimetry is crucial for balancing efficacy and toxicity.

Purpose of the Study:

• To evaluate the efficacy and neurotoxicity of low-dose, homogeneous radiosurgery for benign intracranial tumors.
• To assess treatment outcomes and adverse events in patients treated with a linear accelerator-based X-knife system.
• To determine the effectiveness of this radiosurgical technique in controlling tumor growth and improving patient symptoms.

Main Methods:

• A cohort of 27 patients with benign intracranial tumors (schwannoma, meningioma, etc.) were treated between 1998 and 2000.
• Radiosurgery was performed using a 6-MV linear accelerator with circular collimators, employing low and homogeneous dosimetry (mean peripheral dose 12.8 Gy).
• Follow-up data, including symptom status, tumor response, and neurotoxicity (RTOG grading), were collected for a mean duration of 33 months.

Main Results:

• No tumor progression was observed in any patient.
• Tumor regression occurred in 30% of patients, with 70% showing stable disease.
• Symptom improvement was noted in 22% of patients, and 78% had stable symptoms.
• No high-grade (RTOG grade III/IV) toxicity occurred; only 11% experienced mild (grade I/II) neurotoxicity, primarily mild trigeminal deficits.

Conclusions:

• Low-dose, homogeneous radiosurgery using a linear accelerator is an effective treatment for benign intracranial tumors.
• This technique demonstrates a favorable safety profile with minimal neurotoxicity.
• Further research may explore if lower, more homogeneous radiation doses can achieve durable responses with even greater toxicity reduction.