Rhenium-188-HEDP vs. Radium-223-chloride in Patients With Advanced Prostate Cancer Refractory to Hormonal Therapy

Inclusion Criteria:

* Male, 18 years or older
* Histologically confirmed prostate cancer
* Bone metastases (≥ 6 lesions) showing pathological uptake at bone scintigraphy.
* WHO performance status of ≤2
* Life expectancy of at least 6 months
* Castration-resistant disease: serum testosterone level of ≤ 1.7 nmol per liter (≤50 ng per deciliter) after bilateral orchiectomy or during maintenance treatment consisting of androgen-ablation therapy with a luteinizing hormone-releasing hormone agonist. During study treatment the maintenance androgen-deprivation therapy must be continued.
* Baseline PSA ≥5 ng/ml with evidence of progressively increasing PSA values
* Symptomatic disease with either regular use of analgesic medication or treatment with external-beam radiotherapy for cancer-related bone pain within the previous 12 weeks.
* Progression on or after treatment with docetaxel, or inability to receive docetaxel.
* Adequate renal function (serum creatinine level ≤1.5 x ULN)
* Adequate hematological function defined as absolute neutrophil count ≥ 1.5x10\^9/L and platelet count ≥100x 10\^9/L)
* Written informed consent

Exclusion Criteria:

* Treatment with chemotherapy within the previous 4 weeks
* Continuation of treatment with abiraterone or enzalutamide
* Previous hemibody external radiotherapy
* Systemic radiotherapy with radioisotopes within the previous 24 weeks
* Malignant lymphadenopathy ≥3cm in the short-axis diameter
* Presence of visceral metastases
* Imminent of established spinal cord compression
* Active uncontrolled bacterial, viral or fungal infection
* History of another malignancy within the last five years except adequately treated basal cell carcinoma of the skin
* Organ allografts requiring immunosuppressive therapy.
* Any serious uncontrolled concommitant disease
* Any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule: those conditions should be discussed with the patient before registration in the trial.