ESTRO 2023 - Abstract Book

S1202

Digital Posters

ESTRO 2023

Conclusion This longitudinal analysis showed that urinary symptoms after RT for PCa occur with different persistence. The methodology allowed to identify men with persistent symptoms with and without worsening beyond BL condition and transient symptoms. Despite being the most prevalent, nocturia did not significantly impact long-term QoL. In contrary, incontinence and urgency were associated with much larger worsening in Global Health/QoL.

PO-1484 SBRT for prostate cancer: analysis of CBCT guided radiotherapy and on-line correction

J.A. Solis Campos 1 , L. Gonzalez Abascal 1 , G. Lazcano Álvarez 1 , B. Tudela 1 , G. Veillon Contreras 1 , J. Olivares Gonzalez 2

1 Universidad de Valparaiso, Radiation Oncology, Valparaiso, Chile; 2 Hospital Base de Valdivia, Radiation Oncology, Valdivia, Chile Purpose or Objective Stereotactic body radiotherapy (SBRT) delivers a high radiation dose to an extracranial target in 1 to 5 fractions. The purpose of this study is to describe the treatment characteristics and toxicities in a cohort of prostate cancer patients treated with CBCT guided SBRT without fiducial markers at Carlos Van Buren Hospital (Chile). Materials and Methods We performed a retrospective analysis of patients treated with SBRT using flattening filter free volumetric modulated arc therapy between September 2020 and September 2022. Prescription dose was 36.25 Gy to Prostate PTV and 27.25 Gy to seminal vesicles PTV in five fractions (alternate days). On-line correction was performed before each session with CBCT. Patients were treated in an Elekta, Versa HD with Monaco treatment planning system. Acute and late toxicities were registered according to the RTOG grading system. Results Two hundred eight patients were included. Median follow up was 9.5 months (IQR 6.2-15.6). Median PSA at diagnosis was 10.83 ng / ml (IQR 6.7-22). Forty-five percent (77) of patients had High Risk disease, among them 44% (34) were studied with PSMA PET / CT. Overall, twenty-six percent (45) of patients were staged with PSMA PET / CT. Median IPSS at diagnosis was 8 points (IQR 5-15). Radiotherapy planning was based on MRI-CT fusion in 80.12% (137) of the patients. Thirty-six percent (62) of patients presented acute grade 1-3 gastrointestinal toxicity and 59.06 % (101) presented grade 1-3 acute urinary toxicity. No grade 4-5 toxicity was observed. Late gastrointestinal toxicity was grade 0 in 42.11%, grade 1 in 10.53 %, grade 2 in 3,51% and grade 3 in 0.58%. No grade 4-5 toxicities were reported. Late urinary toxicity was grade 0 in 39.18%, grade 1 in 9.94%, grade 2 in 6.43% and grade 3 in 0.58%, with only one event grade 4 reported. No grade 5 late urinary toxicity was reported.