Radiosurgery for pituitary adenomas: Evaluation of its efficay and safety

Abstract

11515 Background: Pituitary adenomas account for approximately 15% of all primary brain tumors. Multimodality treatment is often necessary and options include medical management, microsurgery, radiotherapy and radiosurgery (RS). Recently, RS has gained acceptance as a complementary treatment since it has been associated with a shorter latency for its effects and lesser morbidity than that of radiotherapy. The objective of this study was to assess the effects of RS on the radiological and hormonal control and its toxicity in the treatment of pituitary adenomas. Methods: It was done a retrospective analysis of the first 26 consecutive patients with pituitary adenomas treated with RS at our institution between 1999 and 2004. RS was delivered with a multiheaded cobalt unit (Gamma Knife). The median radiation dose was 20 Gy defined to the 50% isodose line. Almost 20% of tumors were non-secretory. The remaining were prolactinomas (31%), adrenocorticotropic hormone-secreting (34%) and growth hormone-secreting tumors (15%). Hormonal control was defined as hormonal response (decline of more than 50% from the pre-RS levels) and hormonal normalization. Radiological control was defined as stasis and shrinkage of the tumor. Hypopituitarism and visual deficit were the morbidity outcomes. Hypopituitarism was defined as the initiation of any hormone replacement therapy and visual deficit as loss of visual acuity or visual field after RS. Results: The median follow-up was 40,8 months.Tumor growth was controlled in 96% of the cases and tumor shrinkage ocurred in 8% of the cases. Hormonal control was observed in 14 of 20 (70%) and hormonal normalization in 7 of 20 (35%) patients after RS, with a median latency period of 28,2 months. The 3-year actuarial rate of hormonal control and normalization were 51% and 47,6%, respectively, and the 5-year actuarial rate were 74% and 68,6%, respectively. There were no patients with visual deficit or hypopituitarism after RS. Conclusions: RS is an effective and safe therapeutic option in the management of selected patients with pituitary adenomas. The short latency of the radiation response, the highly acceptable radiological and hormonal control and absence of complications at this early follow-up are consistent with literature. No significant financial relationships to disclose.