Abstract
Most pituitary adenomas are slow-growing, benign tumors that do not exhibit aggressive behavior but instead grow by expansion. The majority of these adenomas can be treated successfully with transsphenoidal resection. However, more than one-third of adenomas are invasive, making complete surgical resection without unacceptable neurological deficits difficult. These more complicated adenomas require multimodal treatment and long-term follow-up for continued favorable outcomes. Initial surgical resection is indicated for decompression of the optic apparatus or cytoreduction before adjuvant therapy, even when gross total resection is not anticipated. Medical therapy is an option for most endocrinologically active adenomas, but nonfunctioning and functional adenomas that do not respond to medical therapy require a multidisciplinary approach. Radiation is often beneficial and can be delivered either as fractionated therapy or in a single dose. Conformal dose planning can be used in most cases to maximize therapeutic benefits. This article reviews the evaluation and treatment of invasive pituitary adenomas and discusses promising new therapies.