3263 - Acute Toxicity of SBRT in Localized Prostate Cancer: A Multicenter Spanish Study
Presenter(s)
S. E. Romero Zoghbi1,2, C. Laria1, D. Sanz-Rosa2, I. J. Thuissard2, C. Andreu-Vázquez2, F. Lopez3, J. Á. García Cuesta4, A. Ocanto2,5, E. Krumina6, J. Fernández7, J. Andreescu Yagüe8, and F. Couñago2,9; 1Departament of Radiation Oncology, GenesisCare, Talavera de la Reina, Spain, 2Department of Medicine, Faculty of Medicine, Health and Sports, European University of Madrid, Madrid, Spain, 3Department of Radiation Oncology, University Hospital Ramón y Cajal, Madrid, Spain, 4Departament of Medical Oncology, GenesisCare, Hospital Universitario San Fransiscode Asis, Madrid, Spain, 5Department of Radiation Oncology, Vithas La Milagrosa University Hospital, Genesis Care, Madrid, Spain, 6Department of Radiation Oncology, GenesisCare, Guadalajara, Spain, 7Department of Radiation Oncology, Centro 360 de Excelencia Oncológica GenesisCare, Barcelona, Spain, 8Department of Radiation Oncology, GenesisCare Córdoba, Córdoba, Spain, 9Department of Radiation Oncology, Hospital San Francisco de Asís y La Milagrosa, GenesisCare, Madrid, Spain
Purpose/Objective(s):
Stereotactic body radiotherapy (SBRT) is an effective option for the treatment of localized prostate cancer. However, evidence of its acute toxicity in real-world clinical practice in Spain is limited. This retrospective multicenter study evaluates acute genitourinary (GU), gastrointestinal (GI), and sexual toxicity in patients treated with SBRT in SpainMaterials/Methods:
251 patients treated with SBRT at 12 Spanish centers between January 2020 and December 2023 were included. The treatment volume encompassed the prostate ± seminal vesicles, without prophylactic pelvic radiotherapy. A dose of 36.25-40 Gy was prescribed in 5 fractions on alternate days. Acute toxicity was assessed up to six months post-treatment according to the CTCAE v5.0 criteria.Results:
The median age was 72 years (range 65-76), and the baseline PSA was 6.7 ng/mL (range 5.3-8.7). The mean dose was 40 Gy (range 35-40 Gy). According to the National Comprehensive Cancer Network (NCCN®) risk classification, 4% of patients were at very low risk, 26.3% at low risk, and 66.5% at intermediate risk (27.1% favorable intermediate and 39.4% unfavorable intermediate). Additionally, 2.8% were at high risk, and 0.4% at very high risk. Most patients (99.2%) received a rectal spacer before treatment. Regarding androgen deprivation therapy (ADT), 66.5% of patients did not receive ADT, 33.5% underwent ADT for =6 months and 3.2% received prolonged ADT (>6 months). GU toxicity = G2 was 6.9% and G3 was 0.4%. GI toxicity = G2 was 0.4%, with no G3 cases. Sexual toxicity = G2 affected 16.1% and G3 affected 1.6% of patients. In multivariate analysis, the penile bulb volume receiving =20% of the dose showed a trend towards a higher risk of sexual toxicity (OR = 2.828; 95% CI: 0.188 - 2.538; P = 0.058).Conclusion:
SBRT in five fractions for localized prostate cancer demonstrated a low acute toxicity profile, with a low incidence of GU, GI, and sexual adverse events. These findings suggest that SBRT is a safe and well-tolerated treatment option in real-world clinical practice in Spain.