30 patients with intermediate / extensive low risk (all core biopsies involvements \> 50%) prostate cancer (not necessitating to treat the nodal regions) will be included in this study. Patient stage T1 - T2, Gleason score ≤ 7, prostate-specific antigen (PSA) ≤ 20 will be considered.
Fiducial gold markers will be introduced in the prostate 1-week before the CT planning. 36 gray (Gy) in 12 fractions using intensity-modulated radiation therapy (IMRT) will be administered to the prostate (margins of 0,5cm) +/- first centimeter of the seminal vesicles.
Brachytherapy boost (15 Gy x 1) dosimetric parameters should respect our current standard (Prostate V100 \> 90% and V150 ≤ 40%, V200 ≤ 15%, Urethra V125 ≤ 1 cc, Rectum V75 ≤ 1cc, Bladder V75 ≤ 1cc). Short course (4 months) hormonal therapy (Degarelix) will be administered to the patient based upon recommended litterature11, 12.
Genitourinary (GU), GI and Sexual toxicity will be self reported. QOL questionnaires will be given to the patients to be answered. Results will be monitored and compared to our currently used standard fractionation regiment.
Follow-up will be scheduled 6 weeks after the implant and every 4 months for the first year, every 6 months for the second year 2 to 5, and on a yearly basis after 5 years. PSA \& testosterone tests will be done every 3 months for the first 3 years, every 6 months on years 4 and 5, and yearly thereafter.
