NRG-GU005: 5-fraction SBRT improves bowel QOL but does not improve 3-year DFS vs MH-IMRT.

SBRT is an ultra-hypofractionated, image-guided radiotherapy regimen (36.25Gy/5 fractions) compared head-to-head with moderately hypofractionated IMRT (70Gy/28 or 60Gy/20) in the Phase 3, international, open-label NRG-GU005 randomized trial (NCT03367702) for localized intermediate-risk prostate cancer (T1–T2b; GG2 with PSA<20 or GG1 with PSA 10–20; n=698). At 2 years, urinary irritative/obstructive MCID rates were similar (35.4% SBRT vs 33.7% MH-IMRT; P=.68), while bowel MCID favored SBRT (34.9% vs 43.8%; P=.03) and grade 3–4 GU AEs were lower with SBRT (0.6% vs 2.5%; P=.04). HAt 3 years, DFS was 88.6% with SBRT vs 92.1% with MH-IMRT; because NRG-GU005 was a superiority trial, the result shows that SBRT did not improve DFS—not that SBRT was proven inferior.