- 5-fraction stereotactic body radiotherapy (SBRT) could safely cut treatment time to 1-2 weeks for patients with low-/intermediate-risk localized prostate cancer.
- Acute gastrointestinal and genitourinary toxicities were similar vs conventionally fractionated or moderately hypofractionated radiotherapy.
Why this matters
- If survival and late toxicity data confirm noninferiority, ultra-hypofractionated radiotherapy will considerably reduce treatment duration.
- Phase 3, noninferiority PACE-B study of 874 patients with performance status 0-2, low-/intermediate-risk prostate adenocarcinoma who were randomly assigned to:
- Conventionally (78 Gy in 39 fractions over 7.8 weeks) or moderately hypofractionated radiotherapy (62 Gy in 20 fractions over 4 weeks).
- Ultra-hypofractionated SBRT (36.25 Gy in 5 fractions over 1-2 weeks).
- Funding: Accuray; National Institute of Health Research.
- Median follow-up was 12 weeks.
- Fractionated radiotherapy and SBRT yielded similar rates of:
- worst Radiation Therapy Oncology Group (RTOG) grade ≥2 severe gastrointestinal toxicities (12% vs 10%; P=.38);
- worst RTOG grade ≥2 severe genitourinary toxicities (27% vs 23%; P=.16);
- worst RTOG grade ≥3 gastrointestinal (1% vs
- No significant differences were observed in international prostate symptom score (IPSS) total, week 12 IPSS total, worst IPSS QoL, or week 12 IPSS QoL scores between the 2 groups.
- No treatment-related deaths reported.
- Open-label design.