S1280
Clinical - Urology
ESTRO 2026
Digital Poster 3943 Clinical and Dosimetric Factors Associated With late Faecal Incontinence After Moderately Hypofractionated VMAT/IGRT for Localised Prostate Cancer Joan Lozano 1,2 , Maria Lizondo 3 , Montserrat Colomer 3 , Josep Maria Solé 1 1 Radiation Oncology, Hospital Universitari de Terrassa, Terrassa, Spain. 2 Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain. 3 Radiation Oncology, Medical Physics Unit, Hospital Universitari de Terrassa, Terrassa, Spain Purpose/Objective: Moderately hypofractionated radiotherapy with VMAT/IGRT is widely used for the treatment of localized prostate cancer. Late side effects in the form of faecal incontinence has been scarcely investigated in this setting. The aim of this study is to explore the clinical and dosimetric determinants associated with post-radiotherapy faecal incontinence in these patients Material/Methods: A prospective cohort of 91 patients treated with moderately hypofractionated VMAT/IGRT for non- metastatic prostate cancer was analysed. Treatment plans were generated using the Monaco treatment planning system and delivered with a VersaHD™ linear accelerator (Elekta AB, Stockholm, Sweden). Faecal incontinence was assessed using the Vaizey scale, with incontinence defined as a Vaizey score ≥ 1 at two years post-treatment. Clinical and dosimetric variables were collected, including minimum, mean, and maximum anal canal and rectal doses, age at radiotherapy, diabetes, haemorrhoids, hormone therapy, and pelvic nodal irradiation. Exploratory univariate analyses were performed (Wilcoxon test for continuous variables and Fisher’s exact test for categorical variables). P-values were adjusted according to the Bonferroni method. A proof-of-concept multivariable logistic regression model was then developed including the most relevant variables. The overall discriminative performance of the model was evaluated using a receiver operating characteristic (ROC) curve. Results: After Bonferroni correction for multiple comparisons, no variable remained statistically significant (p<0.05). However, Anal canal Dmin (adjusted p = 0.799) and haemorrhoids (adjusted p=0.115) showed the strongest associations, and were considered as showing a trend towards significance in this exploratory analysis (Table1). The ROC curve analysis showed good discriminative ability of the model, with an AUC of 0.835 (95% CI: 0.727–0.942, DeLong), (Figure1).
Conclusion: A prolonged time to PSA-nadir after sRT was
associated with increased biochemical recurrence, and this interval correlated positively with PSMA SUVmax. Furthermore, the presence of PSMA-avid lesions on 68Ga-PSMA PET/CT prior to sRT was associated with inferior biochemical control, emphasizing the prognostic relevance of PSMA PET parameters in the salvage RT setting. Keywords: prostate cancer, PSMA, Suvmean, MV, TL- PSMA
Made with FlippingBook - Share PDF online