GAMMA-KNIFE SURGERY FOR SECRETING PITUITARY-ADENOMAS

We report our preliminary results concerning 25 patients with secretin g pituitary adenomas treated with stereotactic radiosurgery after part ial transsphenoidal surgery and followed over a 6-36 month-period. Amo ng the 15 acromegalic patients, a decrease of 65% in mean GH levels wa s achieved after 6 months and of 77% at 12 months after radiosurgery. Presently, only 3 patients (20%) are considered as in remission (mean GH and IGF1 level into the normal range). A decrease of 46% and 64% wa s observed at 6 and 12 months after radiosurgery in 4 patients with pr olactinomas although no normalization of PRL levels occurred. Presentl y, 3/4 patients have individual PRL levels slightly above the normal r ange. A normalization of Urinary Free Cortisol(UFC) was noticed in 4/6 (66%) patients with Gushing's disease within 6-12 months. No pituitar y deficiency was noticed in this series with the exception of 4/25 pat ients (16%) who received subtotal or total pituitary irradiation for p ost-operative remnants of secreting adenomas poorly defined on MRI. On e woman, who had undergone previously a conventional irradiation and p resenting with a cavernous sinus adenoma reaching the optic nerve, dev eloped an optic neuropathy. A second woman, with a cavernous sinus rem nant, presented a cranial nerve palsy (VI) after the irradiation. We c an conclude that radiosurgery using the Cobalt-60 Gamma-unit is, at le ast, as effective as conventional radiotherapy in the control of pitui tary hormone hypersecretion from postoperative adenomas remnants with less adverse effects.