ESTRO 2025 - Abstract Book

S2107

Clinical - Urology

ESTRO 2025

4198

Digital Poster Outcome of Stereotactic Body Radiation Therapy for PSMA-PET Staged Localized Unfavorable Intermediate or High Risk Prostate Cancer Patients Laura Motisi, Tiuri Ewout Kroese, Stephanie Tanadini-Lang, Nicolaus Andratschke, Matthias Guckenberger, Michael Christian Mayinger Radiation Oncology, University Hospital Zürich, Zürich, Switzerland Purpose/Objective: To analyze early outcome after stereotactic body radiation therapy (SBRT) as definitive treatment for patients with PSMA-PET staged localized unfavorable intermediate or high risk prostate cancer in comparison to low/favorable intermediate risk. Material/Methods: Patients treated with definitive SBRT of histologically confirmed prostate cancer (≥18 years, cT1 -3cN0cM0) using CT- or MR-Linac between 2015 and 2023 were analyzed. Risk classification was performed according to NCCN. Delineation of clinical target volumes was according to the risk group and included the prostate only, the prostate with seminal vesicles basis, the prostate with seminal vesicles, or dominant intraprostatic lesion (DIL). SBRT was performed in 5 fractions, with a simultaneous integrated booth (SIB) to either the dominant intraprostatic lesion or to the prostatic CTV ( Table 1 ). Androgen deprivation therapy (ADT) was recommended to all patients with unfavorable intermediate or high/very high risk ( Table 1) . ’