Focal low-dose-rate brachytherapy in patients with localized prostate cancer at low and moderate risk of progression

Aim: to evaluate the dosimetric and functional parameters of focal low-dose-rate brachytherapy in patients with localized prostate cancer (PCa) at low and intermediate risk of progression. Materials and Methods: the study included patients (n=70) with localized PCa of low and intermediate risk, who underwent focal low-dose- rate prostate brachytherapy. The follow-up period was 6 months, with assessments performed at baseline (prior to brachytherapy), at 14 days, 3 months, and 6 months post-procedure. Statistical analysis was performed using RStudio software (version 2024.12.1+563). Results: the median age of patients was 67.0 years (Q1–Q3: 64.0–73.0). Of the total cohort, 67.1% were classified as low risk, and 32.9% as intermediate risk. The dose received by 90% of the tumor volume (D90) was 235.5 Gy, whereas for the prostate gland it was lower, at 130.0 Gy. The median rectal volume receiving 100% of the prescribed dose (rectal V100) was 0.45 cm3; rectal V150 was 0 cm3. Over the 6-month follow- up, significant changes were observed: a decline in prostate-specific antigen (PSA) from 2.6 to 0.6 ng/mL, an increase in International Prostate Symptom Score (IPSS) from 6.3 to 10.3 points, and a decrease in the IIEF-5 (International Index of Erectile Function-5) score from 10.1 to 7.8 points. However, changes in quality of life, assessed by the QoL scale, were not significant. Safety assessment revealed no grade 2 or higher toxic reactions in any patient following focal brachytherapy. Conclusion: the present results indicate the advisability of using focal low-dose-rate brachytherapy in patients with localized PCa of low and intermediate oncological risk as a safe treatment modality. KEYWORDS: prostate cancer, brachytherapy, tumor volume, risk groups, focal radiotherapy, toxic reaction. FOR CITATION: Pavlov A.Yu., Dzidzaria A.G., Tsybulsky A.D., Volodin M.S., Volodina I.V. Focal low-dose-rate brachytherapy in patients with localized prostate cancer at low and moderate risk of progression. Russian Medical Inquiry. 2025;9(7):387–396 (in Russ.). DOI: 10.32364/2587-6821-2025-9-7-3