Advances in Gamma Knife radiosurgery for pituitary tumors.

Abstract

For the residual/recurrent pituitary adenomas, stereotactic radiosurgery (SRS) plays an important role in long-term tumor control and, for secretory adenomas, endocrine remission. The purpose of this review is to address the advances in SRS technique and detail the latest treatment strategies for various types of pituitary adenomas with a focus on recently published literature. From recent publications, SRS may be considered as an upfront treatment in patients with an adenoma that resides largely in the cavernous sinus and for whom resection is unlikely to produce substantial reduction in the overall tumor volume. Early treatment (<6 months after prior resection) with SRS appears to decrease the rate of tumor progression of subtotally resected nonfunctioning pituitary macroadenomas. Some types of adenomas may appear more aggressive with a high recurrence rate, for example, silent corticotroph pituitary adenomas, or sparsely granulated somatotroph-cell adenomas, may be indicated for a high-radiation dose. Finally, whole-sellar radiation and fractionated SRS are the alternative strategies, and may be indicated for challenging cases. The role of SRS for the pituitary adenoma is well established, and the treatment strategy is increasingly individualized based upon tumor histology, location, and volume. Hypopituitarism is the most complicated and can occur even years after SRS.