Gamma knife radiosurgery for growth hormone-producing adenomas.

We evaluated the endocrinological outcomes of gamma knife radiosurgery (GKS) for the treatment of growth hormone (GH)-producing pituitary adenomas. Twenty-six patients treated with GKS (median treatment [tumour] volume: 0.8 mL; median marginal radiation dose: 20Gy) were followed for a median of 84 months. "Disease remission" was defined as either nadir levels of GH <1 microg/L during an oral glucose load, or random GH levels <2 microg/L and normal age-adjusted and sex-adjusted levels of insulin-like growth factor without pituitary suppressive medications. The remission rate was 38% (10/26) and the 5-year and 10-year actuarial remission rates were 16.9% and 47.4%, respectively. Two patients (8%) suffered hypopituitarism requiring medication, but no other serious deficits were observed. Although GKS requires a relatively long time to achieve hormonal remission, it is a very useful, long-term treatment for GH-producing adenomas. We propose that compared to continuing life-long medication, GKS is less invasive and more cost effective.