Genomics and Efficacy of Post-prostatectomy Salvage Radiotherapy With 'Extreme' Hypofractionation

The esSBRT study ("Early salvage stereotactic radiotherapy (esSBRT) for biochemical recurrence after radical prostatectomy: a phase II study", RS1705/22 - opinion of the Central Ethics Committee IRCCS Lazio, Section IFO - Fondazione Bietti of 4 August 2022; NCT05667636) is a prospective phase II study developed and currently active at the Institute's Radiotherapy Unit, in which patients with biochemical recurrence of the disease after RP are treated on the prostatic lodge, and possibly on the pelvic lymph node stations, with hypofractionated radiotherapy in 5 sessions (5 Gy/fx). The aim is to be able to have a genomic classifier, such as Decipher®, for the patients enrolled in this protocol in order to complete the predictive evaluation. Furthermore, the project plans to profile PCa samples using a 'Comprehensive' panel of about 500 genes that allows to identify a specific molecular profile in the respective risk classes (low, intermediate and high) stratified with Decipher®. This evaluation would allow to identify the mutational structure of prostate cancer in an early stage of the disease, in particular by identifying the molecular alterations of the genes involved in homologous recombination repair (HRR) such as BRCA1, BRCA2, ATM, CDK12, CHEK2, PALB2.

The hypothesis is that the Decipher® risk classes (low, intermediate and high) correspond to a different risk of biochemical disease progression (defined as an increase in total PSA of 0.2 ng/ml above the nadir) independently or in addition to conventional clinicopathological criteria.