ESTRO 2025 - Abstract Book

S3852

Physics - Radiomics, functional and biological imaging and outcome prediction

ESTRO 2025

Results: LASSO regression and the Gini selection criteria identified pre-SRT PSA, PSA doubling time, PSMA-PET findings, time from surgery to BCR, ISUP grade, and patient age as key predictors of 2y-bRFS. The primary determinant was pre SRT PSA, with 2y-bRFS rates of 96.2% in patients with PSA < 0.2 ng/mL and 82.7% in those with PSA ≥ 0.2 ng/mL. Among patients with PSA < 0.2 ng/mL and negative PSMA-PET findings, 2y-bRFS reached 100%. For patients with PSA ≥ 0.2 ng/mL, a PSA doubling time >12 months increased 2y-bRFS to 97.2%, compared to 78.1% for those with a doubling time <12 months. Additionally, in this group, patients aged >70 years demonstrated a 2y-bRFS of 100%. ( Figure 1 ) Figure 1 : Predictive model for 2-year biochemical relapse-free survival after salvage radiotherapy (overall rate: 88.2%)

Conclusion: Pre-SRT PSA, PSA doubling time, and PSMA-PET findings play critical roles in managing BCR post-RP, strongly influencing 2y-bRFS outcomes and highlighting the potential need for therapeutic intensification in higher-risk patients. Further research with extended follow-up and the integration of multiparametric MRI is warranted to validate these findings. However, the role of SRT dose in optimizing outcomes remains unclear and requires further investigation.

Keywords: biochemical recurrence, post-prostatectomy

3941

Digital Poster Prototyping digital twins for radiotherapy: patient-specific microvasculature and its evolution during treatment Luca Possenti 1 , Giorgio Aurina 2 , Alberto Calanchi 2 , Francesca Gamba 2 , Pietro Filippo Schgor 2 , Giulia Steiner 2 , Cristina Macaluso 3 , Francesco Pisani 1 , Piermario Vitullo 3 , Alessandro Cicchetti 1 , Nicola Alessandro Iacovelli 4 , Marzia Franceschini 4 , Anna Cavallo 5 , Paolo Zunino 3 , Tiziana Rancati 1 1 Data Science Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 2 Department of Mathematics, Politecnico di Milano, Milan, Italy. 3 MOX, Department of Mathematics, Politecnico di Milano, Milan, Italy. 4 Radiotherapy Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 5 Medical Physics Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy