PSMA-PET Guided Hypofractionated Salvage Prostate Bed Radiotherapy

PSMA-PET Guided Hypofractionated Salvage Prostate Bed Radiotherapy of Biochemical Failure After Radical Prostatectomy for Prostate Cancer

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.

Inclusion Criteria:

• Patients with prostate adenocarcinoma treated with radical prostatectomy;
• Tumour stage pT2-4, R0-1, pN0, or cN0, cNx according to the UICC TNM 2009, only with Gleason score available;
• No lymph node or distant metastases. A recent PSMA-PET scan (< 60 days) without evidence of lymph node or distant metastases;
• PSA progression after prostatectomy defined as two consecutive rises with the final PSA > 0.1 ng/mL or 3 consecutive rises. The first value must be measured at least 6 weeks after radical prostatectomy;
• PSA at inclusion < 1.0 ng/mL;
• WHO performance status 0-2 at inclusion;
• Age at inclusion between 18 and 80 years;
• Written (signed and dated) informed consent prior to registration.

Exclusion Criteria:

• Prior pelvic irradiation, (chemo)hormonal therapy or orchiectomy;
• Previous or concurrent active invasive cancers other than superficial non-melanoma skin cancers;
• Patients with positive nodes or with distant metastases based on the surgical specimen of lymphadenectomy or the following minimum diagnostic workup: PSMA-PET/CT scan, 60 days prior to registration;
• Double-sided metallic hip prosthesis;
• Inability or unwillingness to understand the information on trial-related topics, to give informed consent or to fill out QoL questionnaires.