Stereotactic body radiotherapy (SBRT) re-irradiation for local failures following radical prostatectomy and post-operative radiotherapy.

Abstract

Local recurrences after radical prostatectomy (RP) and postoperative radiotherapy (RT) are challenging for salvage treatment. Retrospective analysis of own experiences with salvage re-irradiation was performed. The study included all consecutive patients treated with salvage stereotactic body radiotherapy (sSBRT) for prostate bed recurrence following RP and postoperative RT at asingle tertiary center between 2014 and 2021. Treatment toxicity defined as the occurrence of CTCAE grade ≥ 2 genito-urinary (GU) or gastro-intestinal (GI) adverse events (AEs) was assessed. APSA response, biochemical control (BC) and overall survival (OS) were also evaluated. The study group included 32patients with amedian age of 68years and amedian follow-up of 41months, treated with CyberKnife (53%) or Linac (47%) sSBRT. Total dose of 33.75-36.25 Gy in five fractions (72%) was applied in the majority of them. Approximately 19% patients reported grade ≥ 2 GU AEs both at baseline and at three months, and grade ≥ 2 GI toxicity increased from 0% at baseline to 6% at three months after sSBRT. There was some clinically relevant increase in late toxicity with 31% patients reporting late ≥ 2 GU, and 12.5% late ≥ 2 GI AEs. Two grade3 AEs were recorded: recto-urinary fistulas. The majority of patients showed aPSA response (91% at one year post-sSBRT). The 3‑year BC was 40% and 3‑year OS was 87%. Manageable toxicity profile and satisfactory biochemical response suggest that SBRT in patients with local recurrence following RP and postoperative RT might be asalvage option for selected patients.