KEY POINTS
- This single-institution retrospective cohort included 300 consecutive patients with low-risk or favourable intermediate-risk prostate cancer treated with real-time transrectal-ultrasound-guided high-dose-rate brachytherapy monotherapy.
- Treatment consisted of 13.5 Gy in two fractions, separated by approximately two weeks and delivered through two separate implants. Low-risk disease accounted for 61.7%, and 12.3% of patients received androgen-deprivation therapy.
- Median prostate D90 was 110.7% of prescription and median V100 was 98.8%. Median urethral Dmax was 114.8%, while median rectal D2 cm³ was 55.8%.
- After a median follow-up of 86.1 months, biochemical progression occurred in 39 patients. Five- and ten-year biochemical progression-free survival was 93.7% and 81.6%, respectively.
- Ten-year biochemical control was 83.7% in low-risk disease and 78.7% in intermediate-risk disease. Ten-year overall survival was 84.8%, and prostate-cancer-specific survival was 98.6%.
- A prostate-specific-antigen nadir of ≤0.2 ng/mL was strongly associated with biochemical control in univariable analysis (hazard ratio 0.04; 95% confidence interval, 0.02–0.09; p < 0.001). No multivariable model was performed because of the limited number of events.
- Late grade 2–3 genitourinary toxicity occurred in 6.7%, including grade 3 events in nine patients. Urethral stricture was the most frequent event; no grade 4 toxicity or grade 2 or higher gastrointestinal toxicity was reported.
CLINICAL TAKEAWAY
These results reinforce 13.5 Gy × 2 high-dose-rate brachytherapy as a durable definitive option for appropriately selected low- and favourable intermediate-risk patients. Prostate-specific-antigen nadir may refine follow-up risk, but it is a delayed post-treatment marker and should not independently trigger intervention without corroborating evidence.