Low-Dose Gamma Knife Radiosurgery for Acromegaly

Area of Science:

• Neurosurgery
• Endocrinology
• Radiation Oncology

Background:

• Higher doses of Gamma Knife Radiosurgery (GKRS) are linked to better remission rates in acromegaly.
• Dose limitations (≥25 Gy) are often necessary for GKRS when functioning adenomas are near the optic apparatus.

Purpose of the Study:

• To assess the effectiveness and safety of low-dose (<25 Gy) GKRS for treating acromegaly.
• To determine if reduced radiation doses can achieve therapeutic goals without compromising patient safety.

Main Methods:

• A retrospective review of 76 acromegaly patients treated with low-dose GKRS between 1994 and 2016.
• Median margin dose of 15.8 Gy, with optic apparatus limited to 10 Gy, and comprehensive endocrine, ophthalmological, and imaging evaluations were performed.

Main Results:

• Biochemical remission was achieved in 43.4% of patients, with actuarial rates reaching 76.3% at 12 years.
• Predictors of remission included absence of cavernous sinus invasion and lower baseline IGF-1 levels.
• New hormone deficiencies occurred in 11.8% of patients, with no optic complications reported.

Conclusions:

• Low-dose GKRS provides acceptable remission rates for acromegaly.
• The efficacy of low-dose GKRS may be comparable to standard doses, offering a safer alternative when critical structures are involved.