The purpose of this randomized trial is to investigate the efficacy and toxicity of percutaneous high-dose radiotherapy in patients with oligometastases of hormone refractory prostate cancer. The effectiveness will be tested in comparison to an observation group, in which no further therapy is initially given. Treatment can be stereotactically hypofractionated or conventionally fractionated.

This is a monocentric, randomized, prospective Phase II intervention trial. Efficacy is measured as the rate in patients with PSA progression one year after randomization (defined as PSA nadir after randomization +2 ng/ml). There is a 2:1 randomization between intervention and observation group. Patients with PSA progression in the observation group are offered a new diagnosis. This should preferably correspond to the initial diagnosis.

Therapy is performed for all patients in the intervention arm using high dose radiation therapy, either as conventional fractional irradiation with 2 Gy/fraction up to a total dose of 50 Gy or as hypofractional irradiation with a single dose of 10 Gy up to a total dose of 30 Gy.

The decision as to which regimen the patient is to be treated according to is made by the treating physician, taking into account in particular the location of the volume to be irradiated in relation to the organs at risk and any previous irradiation.

Indication:

Oligometastases (1-5) in castration-resistant prostate carcinoma

Inclusion Criteria:

• Patient with good general condition (WHO 0-1)
• Histologically confirmed prostate carcinoma
• After definitive local therapy, e.g. radical prostatectomy or definitive radiotherapy (also after neo-adjuvant hormone therapy, after postoperative radiotherapy).
• PSA progression under ongoing androgen deprivation (defined as three consecutive increasing PSA values at intervals of > 4 weeks and testosterone in the castration area <50ng/dl or <1.73nmol/)
• Minimum duration of androgen deprivation 6 months before inclusion in study
• Present complete staging (max. 6 weeks old), preferably by means of PET hybrid imaging with prostate-specific PET tracer
• Imaging detection of individual active or progressive metastases (max. 5, depending on location) that are accessible to local ablative radiotherapy (histological confirmation of the metastases is not required)
• No parallel participation to further clinical therapy trials up to 4 weeks before and after radiation therapy
• Individual case discussion in an interdisciplinary tumor board
• Patient's ability to consent and written consent

Exclusion Criteria:

• Severe concomitant disease that limits further life expectancy to < 5 years according to the physician's assessment.
• PSA > 20ng/ml, testosterone >50 dl or >1,73nmol/l
• visceral metastasis (e.g. lung, liver, brain)
• lack of compliance
• previous taxane-containing chemotherapy