Radiation Therapy in Tumors of the Pituitary Gland

Abstract

Pituitary tumors constitute 10–15% of all primary intracranial tumors and are categorized into two broad classifications: pituitary adenomas, which are benign and do not metastasize to other parts of the body, and pituitary carcinomas, which are malignant and may spread both within the central nervous system (CNS) and outside of it Sivakumar et al. (Neurosurg Focus 31(6):E18, 2011). Most pituitary tumors are benign adenomas affecting the tissues of the anterior pituitary, with pituitary carcinomas and tumors of the posterior pituitary being extremely rare. Pituitary adenomas may be classified as microadenomas, defined as <10 mm in its greatest diameter, or (macro)adenomas, which are ≥10 mm in diameter. The most clinically meaningful designation for an adenoma is its functional status; pituitary adenomas may either be classified as hyperfunctioning adenomas that secrete excess amounts of the hormone typically secreted by the tissue comprising the adenoma or nonfunctioning adenomas, indicating that the adenoma simply occupies anatomic space but does not produce excess hormone secretion.

In this chapter, we will describe the epidemiology, etiology, prevention, detection, anatomy, pathology, workup, and treatment of pituitary tumors. A special emphasis will be placed on radiation therapy as primary treatment, detailing the various radiation techniques that may be utilized. Due to the numerous tissues that constitute the pituitary gland and their location, the manifestations and treatment of these tumors are varied and complex; consequently, optimal management of these tumors requires a treatment team of members of different specialties, including primary care physicians, endocrinologists, radiation oncologists, neurosurgeons, neuroradiologists, otolaryngologists, and neuropathologists.