The North American Gamma Knife Consortium reported outcomes following gamma knife radiosurgery (GKRS) for nonfunctioning pituitary adenomas in 512 patients (93.6% with prior surgical resection) with median 36 months followup (range 1-223 months) and median tumor margin dose of 16 Gy. An overall tumor control rate of 93.4% was observed, and an 85% actuarial 10-year control rate calculated. 58% of patients had hypopituitarism prior to GKRS, and 21% of treated patients had new or worse hypopituitarism. New or progressive cranial nerve dysfunction developed in 9% of patients, with 6.6% sustaining optic nerve dysfunction. No deaths resulted from tumor progression. The “radiosurgical pituitary score” (RPS) criteria were proposed to predict favorable treatment responses: age > 50, no prior radiation, and tumor volume ≤ 5cc. Class I data is not available to compare observation with GKRS for residual nonfunctioning adenomas. The RPS framework is potentially informative for counseling GKRS adenoma patients. Further follow-up of this cohort is needed to ascertain long term durable treatment response.
Journal of Neurosurgery