Inclusion Criteria:

- Histologically verified adenocarcinoma of the prostate.

- Hormone refractory prostate cancer (HRPC) defined as progression during previous
anti-hormone treatment. Patients must have been off previous anti-androgen therapy
for more than 4 weeks.

- Stage IV disease (verified by imaging or clinical examination).

- PSA > 10 microgram/l.

- PSA progression defined as a > 25% increase between two independent measurements
performed with a 1-month interval or more after discontinuation of anti-androgen
treatment.

- Castrate level of testosterone (< 50 ng).

- No previous oestrogen or steroid as metastatic prostate cancer treatment.

- Satisfactory hepatic function in the form of total bilirubin ≤ UNL (upper normal
limit), ASAT/ALAT ≤ 2.5 x UNL, alkaline phosphatase ≤ 5 x UNL.

- Satisfactory renal function, defined as serum creatinine ≤ 1.5 x UNL.

- Satisfactory haematologic function defined as ANC >1.5 x 10^9/l, leucocytes >3.0 x
10^9/l, thrombocytes ≥ 100 x 10^9/l, haemoglobin > 7 mmol/l

- ECOG performance status ≤ 2.

- Life expectancy > 3 months.

- Patient must be able to adhere to protocol requirements.

- Written informed consent.

- > 18 years of age.

Exclusion Criteria:

- Previous prostate cancer treatment with oestrogens or steroid hormones.

- Previous chemotherapy.

- Previous treatment with systemic radioactive isotopes.

- Bisphosphonate treatment (concomitant).

- Radiation therapy covering more than 25% of the bone marrow producing area.

- Other serious coincidental and/or concomitant medical condition.

- Symptomatic cerebral metastases.

- Other previous or current malignant disease, excluding *adequately treated and cured
planocellular skin carcinoma; or *other cancer assessed to carry minimal risk of
recurrence.

- ECOG performance status > 2.