Randomized trials have demonstrated similar treatment outcomes and comparable toxicity with SBRT for prostate cancer. Do those regimens result in similar outcomes when using proton therapy? In this multicenter phase 3 trial, 144 patients with low risk prostate cancer were randomized to receive 38 Gy in 5 fractions using stereotactic body proton therapy (SBPT) or 79.2 Gy in 44 fractions using conventional fractionation (CF). The primary outcome of freedom from failure at the 2 year mark was non-inferior and 100% in each group. It was also non-inferior at 5 years. The rates of grade 2+ GU and GI toxicity at 6 months were 6.8% and 2.3% for SBPT versus 2.2% and 0% for CF. At 2 years, grade 2+ GU and GI toxicity rates were 8% and 4.5% for SBPT versus 11.1% and 6.7% for CF. | Toesca, Int J Radiat Oncol Biol Phys 2024
