ESTRO 2025 - Abstract Book

S2108

Clinical - Urology

ESTRO 2025

Results: In total, 133 patients with a median age of 71 (52- 87) and median PSA level of 10.74 μg/l (0.43 -106) were included. 64 patients presented with low/favorable intermediate, 32 with unfavorable intermediate and 37 with high/very high risk. Only 22/69 patients with minimum unfavorable intermediate risk accepted ADT, of which 4 were unfavorable intermediate and 17 high/very high risk. For all patients, biochemical control after a mean follow-up of 20.3±16.6 months was 98.2% ( Figure 1 ). For patients with, PSA follow-up > 12 months not receiving ADT, mean time to a mean PSA nadir of 0.76 (<0.01- 5.09μg/l) was 21.6±17.1 months. Five patients (3.75%), all of whom did not receive ADT, suffered from biochemical recurrence: an unfavorable intermediate patient presented with biochemical progression without evidence of relapse after 16 months and is under follow-up; a high risk patient developed PSMA-PET defined intra-prostatic recurrence between two DILs, that had received a SIB, after 28 months; a low risk patient developed PSMA-PET defined intra-prostatic relapse in the DIL after 34 months, which had not been treated with a SIB; an unfavorable intermediate patient had a PSMA-PET defined intra-prostatic local and lymphnodal relapse after 34 months and started re-irradiation; a favorable intermediate patient had lymphnodal relapse after 37 months. No acute or late CTCAE toxicities ≥ 3 were reported.

Conclusion: Our results suggest that after a mean follow-up of 20 months, five-fraction SBRT for patients with PSMA-PET staged localized unfavorable intermediate or high/very high-risk prostate cancer is associated with promising biochemical control, despite ADT being rejected by a relevant proportion of patients.

Keywords: Prostate, SBRT, intermediate high risk patients