Salvage high-dose rate brachytherapy for local recurrence of prostate cancer after radical prostatectomy

Background. The current need for optimization of salvage treatment methods is dictated by the growing expansion of indications for radical prostatectomy in many centers in the developed countries of the world. Aim. To evaluate the effectiveness, toxicity, and technical characteristics of high-dose rate brachytherapy in treatment of local prostate cancer (PCa) recurrences after radical prostatectomy. Materials and methods. Between January 2015 and December 2020, salvage high-dose rate brachytherapy was performed in 17 patients at the Russian Scientific Center of Roentgenology and Radiology for local recurrence of PCa after radical prostatectomy. All patients underwent multiparametric magnetic resonance imaging of the pelvis at the stage of primary diagnosis in order to determine macroscopic tissue component in the prostate bed area. To rule out regional and distant metastases, all patients underwent positron emission tomography with 18 F- or 68 Ga-labeled prostate-specific membrane antigen. All patients included in the study underwent perineal biopsy of the prostate bed and seminal vesicles. Results. Median follow-up in the treatment group was 35.7 (24–54) months. Overall survival was 100 %. Prostatespecific antigen-specific survival was 88.2 %. There were no local recurrences of PCa in the treatment group. In patients with local PCa recurrence, significant predictors of treatment failure were the presence of clinically extremely high risk of progression at initial diagnosis ( p = 0.003), development of biochemical relapse up to 24 months after main treatment ( p = 0.001), and increased blood level of prostate-specific antigen above 10 ng/mL during registration of biochemical relapse ( p = 0.002). Conclusion. High-dose rate brachytherapy is a safe and effective salvage treatment for local recurrence of PCa after radical prostatectomy. In addition to the brachytherapy technique, the diagnostic stage is also of great importance providing visualization of the exact location of tumor recurrence.