Inclusion Criteria:  Life expectancy > 10 years Age ≥18 years. World Health Organization (WHO) performance status 0-1. Estimated life expectancy >10 years. Histological evidence of prostate cancer in the prostatectomy specimen Primary tumor, regional nodes, metastasis (TNM): any primary tumor (pT), pathologically node-negative (pN0), M0. Biochemical Recurrence (BCR) after prostatectomy, with 0.15 ≤ PSA <0.70 ng/ml. Patients must be able to comply with the protocol. Signed informed consent. Adequate laboratory findings (Haemoglobin (Hb) >90g/L, absolute neutrophil count >1.0x109/L, platelets >75x109/l, bilirubin <1.5x upper limit of normal (ULN), alanine aminotransferase (ALAT) <5x ULN and creatinine <1.5 ULN).  Exclusion Criteria:  Metastases (regional lymph nodes or distant)* diagnosed with imaging. Prior or ongoing hormonal therapy (antiandrogens or gonadotropin releasing hormone). Prior radiotherapy to the pelvis. Prior malignancy other than prostate cancer and basalioma in the past five years. Clinically significant (i.e. active) cardiovascular disease e.g. myocardial infarction (≤6 months), unstable angina, New York Heart Association (NYHA) class III-IV congestive heart failure. Severe pulmonary disease. Any other serious or uncontrolled illness which in the opinion of the investigator makes it undesirable for the patient to enter the trial.