External beam radiotherapy is a safe and effective curative treatment modality for men with localized prostate cancer (PCa). While traditionally entailing long courses with low daily doses, an appreciation of prostate radiobiology and advancements in radiation delivery have allowed for more abbreviated courses of EBRT. Ultrahypofractionated radiotherapy, which involves the delivery of >5 Gy/fraction, is now considered a standard of care regimen for localized PCa, especially intermediate-risk disease. Stereotactic body radiotherapy (SBRT), a specific form of ultrahypofractionated radiotherapy that utilizes advanced planning, imaging, and treatment technology to deliver in ≤5 fractions, is in particular emerging as a cost-effective, convenient, and safe alternative to longer courses of radiotherapy. Given SBRT’s recent adoption into the standard-of-care armamentarium of PCa treatment and its increasing utilization in this setting, it is important to highlight practical considerations pertaining to patient selection, fractionation scheme, target delineation and planning objectives, particularly when practitioners are faced with difficult clinical situations without clear evidence to provide guidance. The objective of this case-based guide endorsed by the Radiosurgery Society is to provide a practical framework for delivering SBRT to the intact prostate, especially in areas of controversy, illustrated by two challenging cases. In this article, we will discuss common SBRT dose/fractionation schemes and dose constraints for organs-at-risk. We will also review existing evidence and expert opinions on topics such as SBRT dose escalation, utility of rectal spacers, the role of androgen deprivation therapy in the setting of SBRT, SBRT in special patient populations such as those with high-risk disease, large prostate, high baseline urinary symptom burdens and inflammatory bowel disease, as well as new imaging-guidance techniques (e.g. Magnetic Resonance Imaging) for SBRT delivery.Copyright © 2023. Published by Elsevier Inc.
