PSMA-PET Guided Hypofractionated Salvage Prostate Bed Radiotherapy

After radical prostatectomy approximately 15-40% of men develop a biochemical recurrence (BR) within 5 years. The standard treatment of post-prostatectomy BR is salvage external beam radiation therapy (sEBRT). sEBRT can provide long-term disease control; with 5 year biochemical progression-free survival (bPFS) up to 60% and with most treatment failures in the first 2 years after sEBRT. The main goal of this project is to investigate whether the oncologic outcome in patients with post-prostatectomy recurrent PCa can be improved, by increasing the biological effective radiation dose using a hypofractionated schedule of 20 x 3 = 60 Gy. The study is designed as a prospective open phase III randomized multicenter trial. All patients with biochemical recurrence with a PSA \< 1.0 ng/ml after radical prostatectomy for prostate cancer without evidence of lymph nodes or distance metastases will be included. PSA progression after prostatectomy defined as two consecutive rises with the final PSA \> 0.1 ng/mL or three consecutive rises will be included. All eligible patients will be randomized to one of the following two treatment arms: Arm 1 = Conventional sEBRT to apply a total dose of 70 Gy in 35 daily fractions of 2 Gy during 7 weeks. Arm 2 = Hypofractionated sEBRT to apply a total dose of 60 Gy in 20 fractions of 3 Gy during 4 weeks. The primary endpoint will be the 5-year progression-free survival (PFS) after treatment.