ESTRO 2024 - Abstract Book

S2518

Clinical - Urology

ESTRO 2024

2402

Digital Poster

PSMA-guided management of recurrent post-prostatectomy patients

Giuseppe Carlo Iorio 1 , Diego Bongiovanni 1 , Valeria Chiofalo 1 , Cristiano Grossi 1 , Sara Bartoncini 1 , Veronica Richetto 2 , Ilaria Bonavero 1 , Fabio Menegatti 1 , Edoardo Gozzelino 1 , Erica Maria Cuffini 1 , Giuliana Petruzzellis 1 , Marzia Cerrato 1 , Bruna Lo Zito 1 , Chiara Casale 1 , Francesca Catena 1 , Eulalie Joelle Tondji Ngassam 1 , Ramona Parise 1 , Mario Levis 1 , Guido Rovera 3 , Serena Grimaldi 3 , Marco Oderda 4 , Paolo Gontero 4 , Umberto Ricardi 1 1 University of Turin, Department of Oncology, Turin, Italy. 2 University of Turin, Department of Medical Physics, Turin, Italy. 3 University of Turin, Department of Medical Sciences, Nuclear Medicine, Turin, Italy. 4 University of Turin, Department of Surgical Sciences, Urology, Turin, Italy

Purpose/Objective:

To evaluate the impact of PSMA-PET in the management of recurrent prostate cancer (PCa) patients (pts) following radical prostatectomy (RP).

Material/Methods:

This analysis is part of a prospective, open-label, observational, single-center study testing the PSMA-PET performance in recurrent hormone-sensitive PCa pts. Pts with biochemical recurrence (BCR) following RP were staged with PSMA-PET prior to any treatment. Only pN0-pNx were included in the analysis. In case of negative PSMA-PET, pts were treated with salvage prostate-bed (P-bed) RT (SRT) with the addition of ADT at physician discretion. In the case of positive PSMA-PET, a change in management was defined as the P-bed SRT abort or the addition of other therapies, mainly metastases-directed therapy (MDT). Our change in management definition did not include the scenario of a P-bed positive PSMA-PET, eventually guiding RT dose-escalation or impacting ADT lenght. The primary endpoint was biochemical progression-free survival (bPFS) after any treatment following PSMA PET (comparing PSMA-positive vs PSMA-negative pts). Secondary endpoints included: change in management rate, SRT-abort rate, and ADT-free survival in pts treated exclusively with SBRT-based MDT. 108 pts with BCR following RP (pT3=45/108; pN0=84, pNx=24) were staged with PSMA-PET between November 2016 and November 2020. The median follow-up (after the PSMA-PET exam) was 50.9 months. The median PSA at PSMA PET was 0.5 ng/ml. PSMA-PET was positive in 32 pts (29.6%), with 41 lesions overall. The median number of lesions per positive PSMA-PET was 1. Positive regional nodes were detected for 9/32 pts. Positive distant nodes were detected for 4/32 pts; in one case, two distant nodes were simultaneously detected. Positive bone mets were detected in 10 pts; in two cases, two bone mets were simultaneously detected. Two pts had multiple different sites of PSMA-PET positivity: one with positive P-bed and a brain met, and the other had 3 regional nodes and 3 bone mets. A false positive visceral met (thyroid) was initially detected by PSMA-PET but was then ruled out through biopsy. Among PSMA-positive pts, a change in management was necessary for 25/32 pts (78%). Within this cluster of pts, the rate of P-bed SRT abort was 80% (20/25 pts). ADT alone was prescribed in 5/25 pts. 5/25 underwent SBRT + Results: