ABSTRACT
Skillful microsurgical resection holds a central role in the management of skull base tumors, but it is often associated with a steep learning curve and high morbidity; gross total resection is often technically not possible. Stereotactic radiosurgery (SRS) has become a standard of care for management of residual and progressive benign intracranial tumors, and it is also used as an upfront therapy for patients who are deemed unfit for open resection. Single-session SRS is associated with a sustained and high local control rate for benign brain tumors that often exceed 90%. However, single-session SRS is usually contraindicated for treatment of tumors that reside in close proximity or within eloquent intracranial structures, such as the optic apparatus and brainstem. Toward this end, hypofractionated radiosurgery (HFRS) is aimed at integrating the short treatment time and high degree of target conformality of SRS with the benefits of normal tissue repair and repopulation between fractions, as well as the potential to have enhanced tumor cell kill due to re-oxygenation and redistribution to more radiosensitive phases of the cell cycle between fractions. HFRS is typically defined as treating targets in 5 fractions or less at a dose of 5 Gy/fraction and has emerged as a viable treatment alternative in a variety of clinical settings. This chapter reviews the radiobiology of HFRS, discusses practical aspects of HFRS, and also presents a detailed review of clinical series reporting safety and efficacy of HFRS for benign intracranial tumors, including meningiomas, vestibular schwannomas, and pituitary adenomas
