Prospective Evaluation of 68-Ga-prostate Specific Membrane Antigen (PSMA)-Positron Emission Tomograph (PET) and Early Prostatic Specific Antigen (PSA) Kinetics During Salvage Radiotherapy for Personalizing the Management of Men With Relapse of Prostate Cancer After Radical Prostatectomy

Inclusion Criteria: * Histological evidence of prostate cancer in the radical prostatectomy specimen * At least 2 rising PSA values, of which the last ≥ 0.15 ng/ml * Tumor, regional nodes, metastasis (TNM): any T, N0/x, M0/x * Age: 18 years or older * World Health Organization (WHO) performance status 0-1 * Life expectancy \> 10 years * Adequate laboratory findings: hematological: hemoglobin \> 90 g/L (may be transfused to maintain or exceed this level) absolute neutrophil count (ANC) ≥ 1,0 x 109/L, platelets ≥ 75 x 109/L hepatic: bilirubin ≤ 1.5 x upper limit of normal (ULN), alanine aminotransferase (ALAT) ≤ 5 x ULN renal: creatinine ≤ 1.5 x ULN * Signed written informed consent * The patient must be able to comply with the protocol Exclusion Criteria: * Evidence of metastasis on imaging or in specimen (e.g. N1 at lymph-node dissection) * Prior or ongoing treatment with hormones (antiandrogens, GnRH) * Prior radiotherapy to the pelvis * Previous malignancy other than prostate cancer and basalioma the past 5 years. * Clinically significant (i.e. active) cardiovascular disease e.g. myocardial infarction (≤ 6 months), unstable angina, New York Heart Association (NYHA) grade III-IV congestive heart failure * Severe pulmonary disease e.g. pulmonary fibrosis * Any other serious or uncontrolled illness which in the opinion of the investigator makes it undesirable for the patient to enter the trial