Research—Human—Clinical Studies: SpineSpine Stereotactic Body Radiotherapy for Prostate Cancer Metastases and the Impact of Hormone Sensitivity Status on Local ControlAbugharib, Ahmed MD, PhD*,‡; Zeng, K. Liang MD‡; Tseng, Chia-Lin MD‡; Soliman, Hany MD‡; Myrehaug, Sten MD‡; Husain, Zain MD‡; Maralani, Pejman Jabehdar MD§; Larouche, Jeremie MD‖; Cheung, Patrick MD‡; Emmenegger, Urban MD¶; Atenafu, Eshetu G.#; Sahgal, Arjun MD‡; Detsky, Jay S. MD‡ Author Information *Department of Clinical Oncology, Sohag University Hospital, Sohag University, Sohag, Egypt; ‡Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; §Department of Medical Imaging, Neuroradiology Division, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; ‖Department of Surgery, Division of Orthopaedic Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; ¶Division of Medical Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; #Department of Biostatistics, University Health Network, Toronto, Ontario, Canada Correspondence: Jay S. Detsky, MD, Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto,ON, Canada M4N 3M5. Email: [email protected] Presented at the 2020 Annual Meeting of the American Society for Radiation Oncology (ASTRO), October 25, 2020, Virtual Meeting (poster presentation). Neurosurgery: June 2022 - Volume 90 - Issue 6 - p 743-749 doi: 10.1227/neu.0000000000001909 Buy Metrics Abstract BACKGROUND: Stereotactic body radiotherapy (SBRT) is used to deliver ablative dose of radiation to spinal metastases. OBJECTIVE: To report the first dedicated series of spine SBRT specific to prostate cancer (PCa) metastases with outcomes reported according to hormone sensitivity status. METHODS: A prospective database was reviewed identifying patients with PCa treated with spine SBRT. This included those with hormone-sensitive PCa (HSPC) and castrate-resistant PCa (CRPC). The primary end point was MRI-based local control (LC). RESULTS: A total of 183 spine segments in 93 patients were identified; 146 segments had no prior radiation and 37 had been previously radiated; 27 segments were postoperative. The median follow-up was 31 months. At the time of SBRT, 50 patients had HSPC and the remaining 43 had CRPC. The most common fractionation scheme was 24-28 Gy in 2 SBRT fractions (76%). LC rates at 1 and 2 years were 99% and 95% and 94% and 78% for the HSPC and CRPC cohorts, respectively. For patients treated with de novo SBRT, a higher risk of local failure was observed in patients with CRPC (P = .0425). The 1-year and 2-year overall survival rates were significantly longer at 98% and 95% in the HSPC cohort compared with 79% and 65% in the CRPC cohort (P = .0005). The cumulative risk of vertebral compression fracture at 2 years was 10%. CONCLUSION: Favorable LC rates were observed after spine SBRT for PCa metastases; strategies to improve long-term LC in patients with CRPC require further investigation. © Congress of Neurological Surgeons 2022. All rights reserved.