PACE-B
Is five-fraction SBRT non-inferior to conventional or moderately hypofractionated RT for low/intermediate-risk localised prostate cancer?
One underlying study; aliases and follow-up reports consolidated. Primary discipline: Radiation.
874 men with localised low- or intermediate-risk prostate cancer.
Low/intermediate-risk disease; high-risk disease and routine ADT-based treatment outside the primary population.
874 randomised/evaluable as reported.
SBRT 36.25 Gy in five fractions.
78 Gy in 39 fractions or 62 Gy in 20 fractions; ADT was not permitted.
Endpoints and results
Primary freedom from biochemical or clinical failure; late GU/GI toxicity secondary.
- At 5 years, freedom from biochemical/clinical failure 95.8% vs 94.6%.
- HR 0.73 (90% CI 0.48–1.12); p=0.004 for non-inferiority.
- Late grade ≥2 GU toxicity 26.9% vs 18.3% (p<0.001); GI toxicity 10.7% vs 10.2% (p=0.94).
Absolute Effect and outcome visualisation
5-year freedom from failure
% free of failure at 5 years · 5 years. Bars show reported fixed-time percentages.
Interpretation: Non-inferiority, not superiority. Do not calculate benefit NNT from the small numerical difference. Late grade ≥2 GU toxicity excess was 8.6 percentage points; any NNH must be tied to this toxicity endpoint and horizon.
Toxicity, discontinuation and quality of life
Trial-specific harms: Late grade ≥2 GU toxicity increased; late GI toxicity was similar.
Treatment burden/discontinuation: Five treatment visits versus 20–39; substantial convenience advantage.
Quality of life: Use published urinary/bowel/sexual PRO data if quoting numerical differences; none inferred here.
Subgroups, maturity and limitations
Subgroups: Results apply to low/intermediate-risk disease, not high-risk prostate cancer.
Maturity: Five-year primary endpoint follow-up.
Limitations: Control arm includes conventional and moderate hypofractionation; higher late GU toxicity must be weighed against fewer visits.
Five-fraction SBRT is non-inferior for selected localised prostate cancer but increases late urinary toxicity.
Current-practice context must be checked against regional guidelines, patient fitness, biomarkers, alternatives and regulatory status before clinical application. Clinical freshness review and browser-rendered QA remain pending.
Primary sources and registry
Registry: NCT01584258
The Absolute Effect · Updated 26 October 2026 · Never derive NNT from median survival.