Chapter 91 - Stereotactic Radiosurgery for Pituitary Adenomas

Abstract

This chapter discusses the use of stereotactic radiosurgery (SRS) in the treatment of secretory and nonfunctional pituitary adenomas (NFPAs). SRS refers to several modalities that deliver precisely targeted, high-energy photons or protons to target tissue. This energy is delivered as conformal radiation therapy in one or very few fractions with strict control over dosing of adjacent tissue. The main technologies used include Gamma Knife (GK), CyberKnife (CK), linear accelerators (LINACs), and proton beams. SRS for pituitary adenomas is most often used as an adjuvant to surgical resection and medical management to induce biochemical remission of endocrinologically active adenomas or to halt tumor progression in NFPAs. Other modalities of irradiation, such as fractionated radiosurgery (FSR), have also been used and continue to play specific roles in certain clinical scenarios. In many situations, however, the precise outcomes of SRS are still incompletely understood, mostly owing to the lack of data with long-term follow-up. Therefore the care of patients with pituitary adenomas necessitates an interdisciplinary approach with collaboration between endocrinologists, neurosurgeons, radiation oncologists, and ophthalmologists. The approaches, outcomes, and complications of SRS in secretory and nonfunctional adenomas of the pituitary are discussed in the following paragraphs.