Gamma-Knife Surgery for Secreting Pituitary Adenomas

Summary

We report our preliminary results concerning 25 patients with secreting pituitary adenomas treated with stereotactic radiosurgery after partial transsphenoidal surgery and followed over a 6–36 month-period.

Among the 15 acromegalic patients, a decrease of 65% in mean GH levels was 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 65% was observed at 6 and 12 months after radiosurgery in 4 patients with prolactinomas although no normalization of PRL levels occurred. Presently, 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 with Cushing's disease within 6–12 months. No pituitary deficiency was noticed in this series with the exception of 4/25 patients (16%) who received subtotal or total pituitary irradiation for postoperative remnants of secreting adenomas poorly defined on MRI. One woman, who had undergone previously a conventional irradiation and presenting with a cavernous sinus adenoma reaching the optic nerve, developed an optic neuropathy. A second woman, with a cavernous sinus remnant, presented a cranial nerve palsy (VI) after the irradiation.

We can conclude that radiosurgery using the Cobalt-60 Gamma-unit is, at least, as effective as conventional radiotherapy in the control of pituitary hormone hypersecretion from postoperative adenomas remnants with less adverse effects.