ESTRO 2025 - Abstract Book

S2034

Clinical - Urology

ESTRO 2025

3096

Digital Poster Clinical outcomes of treatment intensification in metastatic hormone-sensitive prostate cancer: A multidisciplinary single-center experience Antonio Lazo Prados 1 , Rafael Ordoñez Marmolejo 1 , Fernando Alberca-del Arco 2 , Valery Tarazona Vera 1 , Angel Calvo Tudela 1 , Ana Otero Romero 1 , Raquel Correa Generoso 1 1 Radiation Oncology, Virgen de la Victoria University Hospital, Malaga, Spain. 2 Urology, Virgen de la Victoria University Hospital, Malaga, Spain Purpose/Objective: The objective of this real-world single-center study was to evaluate clinical outcomes and identifies predictive biomarkers for treatment response in patients with metastatic hormone-sensitive prostate cancer (mHSPC) treated with androgen deprivation therapy (ADT) combined with systemic therapies, mainly novel hormonal therapies (NHT), managed by the Urology and Radiation Oncology departments. Material/Methods: We conducted a retrospective analysis on 225 patients with mHSPC treated at a single institution between 2016 and June 2024, with a median follow-up of 13.8 months (0.47-101 months). We evaluated progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier survival analyses. Multivariate Cox proportional hazard models identified significant prognostic factors, and toxicities were categorized using CTCAE criteria. Results: The median age was 70 years (44-89 years), with 93.3% of patients having ECOG 0- 1 and 6.7% ECOG ≥2. High volume disease (CHAARTED criteria) was observed in 45.3%, and 48.9% had high-risk LATITUDE features. Metastases were distributed as M1b (64.9%), M1a (24.9%), and M1c (10.2%). Systemic treatments included apalutamide (38.2%), enzalutamide (19.6%), abiraterone (11.1%), and docetaxel (8%), with 3.1% ADT monotherapy, and 7.6% receiving triplet therapy with darolutamide or 3.1% with abiraterone. Deep PSA nadir (≤0.2 ng/mL) was achieved by 74.7% of patients on apalutamide, 69.4% on enzalutamide, and 47.8% on abiraterone. Achieving a deep PSA nadir correlated significantly with improved survival (p<0.001). Additional survival correlations included CHAARTED low-volume disease (p<0.001) and metachronous metastases (p=0.006). Multivariate analysis confirmed CHAARTED volume (p=0.025) and deep PSA nadir (p=0.06) as independent prognostic factors. Toxicities were reported in 40.1% of patients, with Grade 1 in 18.4%, Grade 2 in 8.2%, Grade 3 in 9.5%, and Grade 4 in 2.7% (hypertension, thrombocytopenia, neutropenia)