ESTRO 2024 - Abstract Book

S2504

Clinical - Urology

ESTRO 2024

2198

Poster Discussion

ABRUPT trial (NCT04831983): initial findings following Radiosurgery for Unfavorable Prostate Tumors

Raffaella Lucchini 1,2 , Maria Belmonte 1,2 , Federica Ferrario 1,2 , Chiara Chissotti 1,2 , Giorgio Purrello 1,2 , Davide Gandola 3 , Cammillo Talei Franzesi 3 , Davide Ippolito 1,3 , Valeria Faccenda 4 , Denis Panizza 1,4 , Stefano Arcangeli 1,2 1 University of Milan Bicocca, School of Medicine and Surgery, Milano, Italy. 2 Fondazione IRCCS San Gerardo dei Tintori, Radiation Oncology, Monza, Italy. 3 Fondazione IRCCS San Gerardo dei Tintori, Diagnostic Radiology, Monza, Italy. 4 Fondazione IRCCS San Gerardo dei Tintori, Medical Physics, Monza, Italy

Purpose/Objective:

To evaluate early gastrointestinal (GI) and genitourinary (GU) side effects and diffusion-weighted (DW) Magnetic Resonance Imaging (MRI) changes in patients with organ-confined unfavorable Prostate Cancer (PCa) following Radiosurgery (RS).

Material/Methods:

Thirty patients with histologically proven organ-confined intermediate unfavorable or selected high-risk PCa enrolled in the prospective clinical trial ‘‘ABRUPT” (NCT04831983) were treated with a single fraction of 24 Gy to the whole prostate with urethral sparing (Figure 1) in association with Androgen Deprivation Therapy (ADT), as per standard of care. The treatment was delivered on Linac platform with Volumetric Modulated Arc Therapy (VMAT) and a real-time prostate tracking system. Toxicity was evaluated with CTCAE_v5 scale. IPSS, IIEF scores and Quality of Life (QoL) metrics assessed with EORTC QLQ-PR25/-C30 questionnaires were also measured. The Minimal Clinically Important Change (MCIC) indicating worsening was defined as a change in the questionnaire score of > 0.5 Standard Deviation (SD). In addition, the median Apparent Diffusion Coefficient (ADC) value was registered at the level of the Dominant Intraprostatic Lesion (DIL) before RS (time 0), one-hour post-RS (time 1), and 3-month after treatment (time 2).

Results: