[The usefulness of adjuvant therapy using gamma knife radiosurgery for the recurrent or residual nonfunctioning pituitary adenomas].

We evaluated the treatment results of nonfunctioning pituitary adenomas in the era of radiosurgery. Between January 1994 and December 2003, we operated on 44 patients with nonfunctioning pituitary adenomas. 43 patients were operated on by transsphenoidal surgery and one patient was operated on by the transcranial approach. Total removal was able to be achieved in 13 patients (30%). Gamma knife radiosurgery was performed for residual tumor in 26 patients and for recurrence in 2 patients. The mean tumor diameter at the gamma knife radiosurgery was 18.2 mm (7.9 to 26.3 mm). The treatment dose was a mean of 12.3 Gy (8 to 16 Gy) to the tumor margin. The mean follow-up period after radiosurgery was 36.4 months. Tumor growth control was able to be achieved in 26 patients (93%). Two patients (7%) required adrenal and thyroid hormonal replacement during the follow-up period after radiosurgery due to radiation-induced endocrinopathy. None of the patients suffered from new cranial nerve deficits. This included optic neuropathy. Surgical resection using transsphenoidal surgery and subsequent gamma knife radiosurgery for residual and recurrent tumor proved to have a highly effective tumor growth control rate, and maintained the quality of life in patients with nonfunctioning pituitary adenomas.