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

PurposeLocal 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.MethodsThe study included all consecutive patients treated with salvage stereotactic body radiotherapy (sSBRT) for prostate bed recurrence following RP and postoperative RT at a single 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. A PSA response, biochemical control (BC) and overall survival (OS) were also evaluated.ResultsThe study group included 32 patients with a median age of 68 years and a median follow-up of 41 months, 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 grade 3 AEs were recorded: recto-urinary fistulas. The majority of patients showed a PSA response (91% at one year post-sSBRT). The 3-year BC was 40% and 3-year OS was 87%.ConclusionsManageable toxicity profile and satisfactory biochemical response suggest that SBRT in patients with local recurrence following RP and postoperative RT might be a salvage option for selected patients.