Short-term endocrinological results after gamma knife surgery of pituitary adenomas.

We report our preliminary results after the radiosurgical treatment of 25 secreting pituitary adenomas with a mean follow-up of 20 months (range 6-36 months). Fifteen acromegalic patients showed a decrease of 65% in mean growth hormone (GH) levels after 6 months and of 77% after 12 months. Only 3 patients (20%) are considered to be in remission (mean GH and IGF1 level into the normal range). A decrease of prolactin (PRL) was noted in 46% and 64% at 6 and 12 months after radiosurgery in 4 patients with prolactinomas. There was no case of PRL normalizaion. At present 3/4 patients have individual PRL levels slightly above the normal range. A normalization of Urinary Free Cortisol (UFC) was noticed in 4/6 (66%) patients Cushing's disease within 6-12 months. Pituitary deficiency was noticed in this series in 4/25 patients (16%) who received subtotal or total pituitary irradiation for large postoperative remnants of secreting adenomas poorly defined on magnetic resonance imaging (MRI).