Stereotactic radiosurgery for tectal low-grade gliomas

Area of Science:

• Neurosurgery
• Radiation Oncology
• Neuropathology

Background:

• Low-grade gliomas in the midbrain tectal region present unique treatment challenges due to their deep location.
• Traditional treatment options may be limited or associated with significant morbidity.

Purpose of the Study:

• To evaluate the efficacy and safety of Leksell Gamma Knife radiosurgery for tectal low-grade gliomas.
• To determine optimal radiation dosing parameters to maximize tumor control and minimize complications.

Main Methods:

• Retrospective analysis of 7 patients with tectal low-grade gliomas treated with Gamma Knife radiosurgery between 1979 and present.
• All treatments utilized a single isocenter with a 14 mm collimator, with peripheral doses ranging from 14 to 35 Gy.
• Tumor response and clinical outcomes, including adverse events, were assessed post-treatment.

Main Results:

• Six out of seven tumors showed complete response (disappearance or cessation of growth) following radiosurgery.
• Initial cases treated with higher peripheral doses (30-35 Gy) experienced severe radio-induced edema and permanent deficits.
• Lower peripheral doses (≤14 Gy) were associated with successful tumor control and fewer adverse events.

Conclusions:

• Leksell Gamma Knife radiosurgery is an effective treatment modality for deeply located low-grade gliomas in the tectal region.
• Careful patient selection and precise dose prescription, particularly limiting peripheral doses to 14 Gy, are essential for safe and effective treatment.
• Avoiding high peripheral doses is critical to prevent severe radio-induced complications.