ESTRO 2024 - Abstract Book

S2434

Clinical - Urology

ESTRO 2024

Results:

A total of 100 patients are enrolled in the trial and equally randomized in the two treatment arms. As of today, plasma samples were collected for a total of 83 patients. When samples collection will be completed for all the enrolled patients the ctDNA extraction and the subsequent next-generation sequencing will be performed as described in the methods section. The definition of a high-risk mutational signature will be pursued across the whole mutational panel. In addition, in order to validate the results of the molecular analyses within the STOMP e ORIOLE trials1, the presence of a pathogenic somatic mutations within ATM, BRCA1/2, Rb1, and TP53 genes will be tested. For patients with available tissue specimen (from bioptic or surgical samples of the primary tumor), the mutational signature will be longitudinally validated both in tissue and plasma samples. Oncological results of the RADIOSA trial reported a 66% rate of clinical progression (29/50 patients) in the SBRT alone arm (arm A) vs the 34% rate in the combinatorial arm (SBRT + ADT, arm B); with a median time to clinical progression more than doubled for the latter (15 months arm A vs 33 months arm B). Of particular interest will be the molecular characterization of the subgroup of patients in the arm A who did not developed a recurrence, since they could represent the ideal candidate for the metastasis-directed therapy (MDT).

Conclusion:

Mutational landscape data from ctDNA of the enrolled patients with next-generation sequencing (NGS) analyses are currently ongoing and results will be available before the late-breaking abstract submission deadline. The longitudinal validation of these results in the bioptic samples and the overall analyses will hopefully offer a valuable piece of evidence to be integrated with next-generation imaging to better stratify oligometastatic patients according to whether they benefit from more or less aggressive therapies.

Keywords: prostate cancer, RADIOSA trial, molecular biology

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