SBRT Misses the Mark in Prostate Cancer Trial

In the NRG Oncology GU005 randomized trial (JAMA, n=698), stereotactic body radiotherapy (36.25 Gy in 5 fractions) was compared with moderately hypofractionated IMRT (70 Gy/28 or 60 Gy/20) in localized prostate cancer. At 2 years, fewer patients on SBRT reported a clinically important decline in the EPIC-26 bowel domain (34.9% vs 43.8%; P=.03), while the urinary irritative/obstructive domain showed no difference (35.4% vs 33.7%; P=.68). Three-year disease-free survival was 92.1% (95% CI, 88.9%-95.2%) with hypofractionated IMRT versus 88.6% (95% CI, 85.2%-92.1%) with SBRT. SBRT therefore shortens treatment and eases bowel symptoms, but did not improve urinary symptoms and did not show better disease control in this trial.