Adjuvant Gamma Knife radiosurgery in non-functioning pituitary adenomas; low risk of long-term complications in selected patients.

Complete surgical removal of non-functioning pituitary adenomas is often not possible. This retrospective study aimed at evaluating the long-term outcome and complications of Gamma Knife (GK) radiosurgery adjuvant to pituitary microsurgery in selected patients with small tumour remnants treated 1994-2004. Thirteen men and ten women, median age 49 years, were identified. Prior to GK 15 patients had remaining pituitary function. Median size of the tumours was 1.1 cm(3). Median marginal dose was 20 Gy. Median follow-up with MR imaging was 78 and 97 months for clinical evaluation. Tumour growth control was 100%, irrespectively of growth hormone (GH) therapy for 72 months (n = 10). Only one recurrence was discovered outside radiation field and no new hypopituitarism was developed. This report suggests that in well-selected patients the long-term risk of complications is low and with careful surveillance GH insufficiency can be replaced. Lifelong follow-up is mandatory.