ESTRO 2024 - Abstract Book

S2328

Clinical - Urology

ESTRO 2024

the analysis. Primary endpoint was rate of acute and late gastrointestinal (GI) and genitourinary (GU) toxicity reported according to Common Terminology Criteria for Adverse Events (CTCAE).

Results:

Overall, 302 patients were included in the current analysis. All patients were treated with stereotactic body radiotherapy (SBRT) for a median total dose of 30 Gy in 2-5 fractions. Concomitant ADT was administered in 177 patients. After 42 months of median follow up (95% CI 37-48 months), rate of acute GI toxicity was 11.2% (29 G1 and 5 G2 events, respectively), while acute GU toxicity was reported in 22.5% of patients (56 G1 and 12 G2 events, respectively). Late GI toxicity was recorded in 20.2% of patients (38 G1, 17 G2, 5 G3 and 1 G4 events, respectively), while rate of late GU toxicity was 38.4% (68 G1, 34 G2, 6 G3 and 8 G4 events, respectively). Biochemical relapse-free, metastasis-free, and overall survival (BRFS, MFS and OS) data were available for 287, 291 and 296 patients, with 171, 77 and 65 events, respectively. Median BRFS, MFS and OS were 30 months (95% CI 24-34 months), not reached (95% CI NR-NR) and 98 months (95% CI 81-142). At univariate analysis, baseline high-risk disease (p=0.01), time between end of first radiotherapy course and relapse ≤36 months (p<0.001), concomitant ADT (p<0.001), and PSA at relapse ≤1 ng/ml (p=0.001) were all significantly associated with BRFS, and persisted as independent prognostic factors at multivariate analysis. None of the abovementioned factors was significantly associated with MFS. Only time between end of first radiotherapy course and relapse ≤36 months was significantly associated with OS (p=0.02).

Conclusion:

After more than 3 years of median follow up, toxicity rate after reirradiation was mild, and clinical outcomes in terms of BRFS, MFS and OS were promising. RE-START is a multicentric international registry including long term follow-up data about patients undergoing reirradiation for macroscopic relapse within prostate or prostate bed, that could provide reliable information about implementation of this approach in current clinical practice.

Keywords: Prostate, recurrence, retreatment

References:

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2) Ingrosso G, Becherini C, Lancia A, Caini S, Ost P, Francolini G, et al. Nonsurgical Salvage Local Therapies for Radiorecurrent Prostate Cancer: A Systematic Review and Meta- analysis. Eur Urol Oncol. 2020 Apr;3(2):183-197.

3) Valle LF, Lehrer EJ, Markovic D, Elashoff D, Levin-Epstein R, Karnes RJ, Reiter RE, Rettig M, Calais J, Nickols NG, Dess RT, Spratt DE, Steinberg ML, Nguyen PL, Davis BJ, Zaorsky NG, Kishan AU. A Systematic Review and Meta-analysis of Local Salvage Therapies After Radiotherapy for Prostate Cancer (MASTER). Eur Urol. 2021 Sep;80(3):280-292.