A Trial Evaluating Toxicity of SBRT and LDRB in Localized Prostate Cancer.

Low-dose rate brachytherapy (LDRB) using Iodine-125 seed implant is known to be an effective definitive treatment for patients with low and favourable intermediate-risk prostate cancer. Mature data from Canadian institutions reported a biochemical progression-free survival as high as 90-95% at 5-10 years for patients with low and intermediate risk disease. Prostate Stereotactic Body Radiotherapy (SBRT) as a single modality is a promising alternative to LDRB in low and favourable intermediate-risk prostate cancer. Some studies have shown the feasibility and efficacy of SBRT with low to intermediate risk-prostate cancer with 5-7 years PSA-progression-free survival really high (89,8% to 97,1% at a median follow-up of 5-7 years) \[PSA: Prostate-Specific Antigen\]. No randomized trial has yet compared LDRB to SBRT head to head. Acute urinary toxicity is not trivial: a few studies have shown correlation between late urinary toxicity and the presence of acute urinary toxicity in patients treated with LDRB. Our research hypothesis is that SBRT for low and intermediate risk will result in fewer toxicities at the genito-urinary and the gastro-intestinal levels after 3 months of treatment.