Gamma Knife (GK) Radiosurgery for Pituitary Adenomas: Evaluation of a Series of 163 Patients

AbstractWe have analyzed a group of 163 patients with pituitary adenoma treated by the GK for 5 years. They were followed up for 12 –60 months (median 24 months) after irradiation. An antiproliferative effect has been achieved using the minimal dose 16–35 Gy with median of 20 Gy to the tumor margin in all of our patients who were controlled by MRI (n = 126 patients). One-half of these adenomas noticeably decreased in size. T his antiproliferative dose was safe for the surrounding structures. The effect was not dependent on the gender or age of the patient, on previous fractionated radiotherapy, or on the applied dose. A significant dependence was found on the invasive growth of adenoma, on the use of a modern planning s ystem (GammaPlan) in relation to the older Kula system, and on previous microsurgery. The hormonal normalization has been achieved in 50.4% from 133 hypersecreting adenomas (39/91 = 43% of acromegalics, 11/13 = 85% of patients with Cushing's disease, 2/9 = 22% of patients with Nelson's syndrome, 11/ 18 = 61% of prolactinomas). The median latency of the effect was 12 months. The minimal dose to the margin of hypersecreting adenomas was 10--45 Gy, median 35 Gy. The hormonal normalization was not dependent on the gender, on previous surgical resection, fractionated radiotherapy, or on the volume o f adenoma. The dependence of the treatment result could be proved in relation to the age, the invasive growth of the tumor, the level of its hypersecretion, the siz...

Source: Journal of Radiosurgery - September 1, 2000 Category: Radiology Source Type: research