KEY POINTS
- This retrospective single-centre cohort included 607 men with localized prostate cancer treated between 2012 and 2023. Median follow-up was 70 months, 73.4% had NCCN high-risk disease, and approximately two-thirds were CPG 4-5.
- All patients received a single 15 Gy HDR brachytherapy boost combined with EBRT. External-beam schedules were 46 Gy in 23 fractions in 90.9% and 37.5 Gy in 15 fractions in 9.1%. ADT was used in 99.3%, most commonly for two or three years.
- Disease control remained high at six years: biochemical progression-free survival was 94.1%, metastasis-free survival 94.2%, overall survival 92.7%, and prostate cancer-specific survival 98.1%.
- Outcomes differed substantially by risk. Six-year biochemical control was 99.3% in intermediate-unfavorable disease versus 89.7% in high-risk disease, and no metastatic events were observed among the intermediate-unfavorable patients.
- ISUP grade remained strongly prognostic. Patients with ISUP grade 5 had six-year biochemical control of 85.2%, metastasis-free survival of 88.6%, prostate cancer-specific survival of 93.5%, and overall survival of 90.3%.
- Severe late toxicity was uncommon. Overall late grade 3-4 GI/GU toxicity occurred in 2.6%, including grade 3 GU toxicity in 2.0% and grade 3 GI toxicity in 0.3%. Urethral stricture occurred in 2.5%, and 1.8% required pads for urinary incontinence.
- Delivering HDR brachytherapy before versus after EBRT was not associated with meaningful differences in biochemical control, metastasis-free survival, overall survival, prostate cancer-specific survival or severe late toxicity, supporting scheduling flexibility.
- Interpretation is limited by the retrospective, single-centre design and near-universal long-term ADT. Lower-grade urinary, bowel and sexual toxicity was not systematically collected, and evolving use of PSMA PET may have affected metastatic detection over the study period. 7 Brachy
CLINICAL TAKEAWAY
A single 15 Gy HDR boost combined with EBRT and ADT produced durable disease control with low rates of severe late toxicity in a predominantly high-risk population. The large cohort and mature follow-up make these useful contemporary benchmarks, although the nonrandomized design prevents comparison with alternative dose-escalation strategies.