Radiosurgery For Pituitary Adenomas: Evaluation Of Its Efficacy And Safety

Douglas Castro1, Soraya Aurani J.1, Miguel Montes Canteras1

1Institute of Neurologic Radiosurgery, São Paulo, Brazil.

Keywords: gamma knife, pituitary adenoma, radiosurgery, hormone dysfunction, outcome

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     The objective of this study was to assess the effects of radiosurgery (RS) on the radiological and hormonal control and its toxicity in the treatment of pituitary adenomas.
     Retrospective analysis of 42 patients out of the first 48 consecutive patients with pituitary adenomas treated with RS between 1999 and 2008 with a 6 months minimum follow-up. There were 14 patients with non-secretory adenomas and, among functioning adenomas, 9 were prolactinomas, 9 were adrenocorticotropic hormone-secreting and 10 were growth hormone-secreting tumors.
     RS was delivered with Gamma Knife as a primary or adjuvant treatment. 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. The median dose was 12,5 Gy (9 – 15 Gy) and 20 Gy (12 – 28 Gy) for non-secretory and secretory adenomas, respectively. The median target volume was 1,2 mL (0,03 - 11,1 mL).
     The median follow-up was 42 months (6 - 109 months). Tumor growth was controlled in 98% (41 in 42) of the cases and tumor shrinkage ocurred in 10% (4 in 42) of the cases. The 3-year actuarial rate of hormonal control and normalization were 62,4% and 37,6%, respectively, and the 5-year actuarial rate were 81,2% and 55,4%, respectively. The median latency period for hormonal control and normalization was, respectively, 15 and 18 months. On univariate analysis, there were no relationships between median dose or tumoral volume and hormonal control or normalization. There were no patients with visual deficit and 1 patient had hypopituitarism after RS.
     This is a retrospective study.
     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.


Project Roles:

D. Castro (), S. J. (), M. Canteras ()