Stereotactic Body Radiotherapy for Localized Prostate Cancer: A Narrative Mini-Review of Contemporary Evidence

Stereotactic body radiotherapy (SBRT) has evolved from an experimental ultrahypofractionation strategy into a guideline-endorsed standard-of-care option for localized prostate cancer, underpinned by the tumour’s low α/β ratio. Level 1 evidence from the PACE-B and HYPO-RT-PC trials establishes five- and seven-fraction regimens as non-inferior to conventionally or moderately hypofractionated radiotherapy in low- and favourable intermediate-risk disease, with comparable long-term toxicity despite a transient increase in genitourinary morbidity. Extension of SBRT to unfavourable intermediate- and high-risk disease, currently being tested in the PACE-C trial and supported by pooled Stereotactic Body Radiotherapy for High-risk Localized Carcinoma of the Prostate (SHARP) consortium data, shows encouraging early efficacy and an acceptable toxicity profile when combined with androgen deprivation therapy, although mature comparative efficacy data remain pending. Technical refinements — particularly magnetic resonance imaging (MRI)-guided delivery with aggressive margin reduction, as demonstrated in the MIRAGE trial — substantially reduce acute and late genitourinary and gastrointestinal toxicity relative to computed tomography-guided delivery. Elective pelvic nodal irradiation using SBRT technique remains investigational pending results of the PACE-NODES trial. Current National Comprehensive Cancer Network, American Urological Association/American Society for Radiation Oncology, and European Society for Radiotherapy and Oncology–Advisory Committee on Radiation Oncology Practice guidance endorses SBRT across risk groups, with continued caution regarding high-risk and nodal applications outside clinical trials. Health-economic analyses consistently favour SBRT over intensity-modulated radiotherapy on cost-effectiveness grounds. This review synthesizes contemporary randomized and pooled-cohort evidence, current guideline recommendations, and emerging technical directions to inform patient selection and treatment delivery for prostate SBRT.