KEY POINTS
- This prospective, multicenter, single-arm phase 1/2 nonrandomized trial enrolled 45 patients with low- or intermediate-risk localized prostate cancer; 43 received treatment per protocol.
- Treatment consisted of urethra-sparing stereotactic body radiotherapy delivered as 19 Gy in 1 fraction, with intrafraction motion monitoring.
- After a median follow-up of 55.3 months, estimated three-year biochemical relapse-free survival was 92.9% (95% confidence interval 85.4%–100%), meeting the predefined primary endpoint because the expected value of 96% was contained within the confidence interval.
- At three years, grade 2 genitourinary and gastrointestinal adverse events occurred in 9.8% and 4.9% of patients, respectively. One patient developed grade 3 proctitis at 12 months.
- Grade 2 or higher erectile dysfunction increased from 21.4% at baseline to 38.4% at three years; clinically meaningful deterioration in urinary and sexual quality-of-life scores occurred in 14% and 28%, respectively.
CLINICAL TAKEAWAY
Single-fraction 19-Gy stereotactic body radiotherapy appears feasible for carefully selected patients with low- or intermediate-risk localized prostate cancer when urethral sparing and intrafraction motion control are available. The findings are encouraging but not practice-changing because the trial was small, nonrandomized, excluded significant transitional-zone disease, and requires longer follow-up for durable disease control and late toxicity.