ESTRO 2024 - Abstract Book

S2608

Clinical - Urology

ESTRO 2024

Andrei Fodor 1 , Chiara Brombin 2,3 , Laura Giannini 1 , Chiara Lucrezia Deantoni 1 , Miriam Torrisi 1 , Italo Dell'Oca 1 , Paola Mangili 4 , Paola Maria Vittoria Rancoita 2,5 , Martina Midulla 1 , Cesare Cozzarini 1 , Paola Mapelli 6 , Maria Picchio 6,5 , Antonella Del Vecchio 4 , Claudio Fiorino 1 , Mariaclelia Stefania Di Serio 2,7 , Nadia Gisella Di Muzio 1,5 1 IRCCS San Raffaele Scientific Institute, Department of Radiation Oncology, Milano, Italy. 2 Vita-Salute San Raffaele University, University Center for Statistics in the Biomedical Sciences, Milan, Italy. 3 Vita-Salute San Raffaele University, Faculty of Psychology, Milan, Italy. 4 IRCCS San Raffaele Scientific Institute, Medical Physics, Milano, Italy. 5 Vita-Salute San Raffaele University, Faculty of Medicine and Surgery, Milan, Italy. 6 IRCCS San Raffaele Scientific Institute, Department of Nuclear Medicine, Milano, Italy. 7 Vita-Salute San Raffaele University, Medical Statistics and Epidemiology, Milan, Italy Extended nodal radiotherapy (ENRT) determines better biochemical control for patients with prostate cancer both for radical radiotherapy and for salvage treatments after surgery, in prospective randomized phase III trials (POP-RT and NRG Oncology/RTOG 0534 SPPORT trial) [1,2]. There are no phase III trials comparing ENRT vs metastasis directed therapy (MDT) for lymph-nodal metastases (LNM) of prostate cancer, but a large multi-institutional retrospective analysis observed better outcomes for selected patients treated with ENRT [3]. In prospective cohorts of patients ENRT determines long clinical relapse free survival [4, 5]. Here we report the results of a preliminary analysis in two cohorts of patients treated with salvage ENRT and positron emission tomography (PET)-guided simultaneous integrated boost (SIB) on PET positive LNM (ENRT group) and PET guided MDT (MDT group), in a mono-institutional analysis. Purpose/Objective:

Material/Methods:

From 02/2005 to 11/2021, 305 patients were treated for 781 LNM with ENRT or MDT for prostate cancer LNM. Given that in some patients the treatments were repeated for subsequent relapses, only the first treatment was considered for this analysis. First MDT treatments for synchronous metastases were considered together, as a single treatment, even when they were delivered with different treatment plans, because they concerned different districts. Thus, 199 patients treated with ENRT at a median total dose (TD)= 51.8 Gy/28 fr, and PET-guided SIB on PET+ LNM to a median TD= 65.5 (50-74.2) Gy in 28 (25-30) fractions, and 33 patients treated with MDT at a median TD=35 Gy (25-65) in 5 (3-30) fractions were included in the analysis. Median number of metastases per patient was 2 (1-32) for ENRT patients and 1 (1-4) for MDT patients. [11C]-Choline PET/CT was used for 188 patients and [18F]- PSMA PET/CT for 42 patients.

Results: