Inclusion Criteria:

- Age >= 75

- Histologically proven prostate adenocarcinoma

- Metastatic disease, not pre-treated with chemotherapy refractory to castration

- Hormone refractory prostate cancer is defined as follows:

- Patients with documented testosterone castration (<0.50 ng / ml)

- Patient who received prior hormonal therapy (either orchidectomy or Luteinizing
hormone-releasing hormone (LHRH) agonist alone or combined with an
anti-androgen)

- Patients should continue primary androgen suppression by LHRH agonist (in case
of non-surgical castration)

- For patients treated with anti-androgens prior to inclusion, a wash-out period
is required (4 weeks for flutamide and nilutamide, 6 weeks for other products)
as well as measured progression after anti-androgen discontinuation.

- Progressive disease under hormonotherapy, with progression defined by

Increase of PSA level (two consecutive increases of PSA compared to baseline with a
minimum of one week between both measurements)

OR emergence of a new lesion

OR measurable progressive disease (increase of a previous measurable lesion >= 25% in
cross section)

OR progressive bone metastases (defined only by the appearance of a new lesion on bone
scan)

OR progressive symptoms (defined as cancer pain Grade 2 according to the NCI-CTC V4.0,
despite level 2 analgesics intake).

- Patients of Groups 2 and 3 [ "vulnerable" and "frail"] of SIOG classification

- WHO Performance Status (PS) >= 3

- PSA >= 5 ng / ml

- Neutrophils >= 2.109 /L

- Platelets >= 100.109/L

- Haemoglobin ≥ 9 g/dl

- Bilirubin and SGOT / SGPT <1.5 x ULN (<= 2.5 x ULN if hepatic metastasis)

- creatinine <= 2.5 x ULN

- In case of previous palliative or analgesic radiotherapy, a minimum of 14 days must
have elapsed between end of radiotherapy and inclusion into the study

- Previous treatment with bisphosphonates should be continued without change during the
study treatment and can not be initiated either within 28 days prior to study entry
or during the study

- Signed informed consent by patients, according to local regulations

Exclusion Criteria:

- "healthy" or "terminal illness" Groups according to the recommendations of
International Society of Geriatric Oncology (SIOG)

- Concomitant or previous malignancy within 5 years prior the study (except basal or
squamous in situ cell skin carcinoma)

- Presence of brain metastasis symptoms

- Prior treatment by intravenous radiopharmaceutical agent (e.g. Strontium 89, Samarium
lexidronam) within 2 months before study entry

- Initiation of a bisphosphonate therapy within 28 days prior to randomisation

- Any concomitant anticancer treatment (radiotherapy, radiopharmaceutical agent,
chemotherapy)

- Patients with uncontrolled infection

- Patients with peripheral neuropathy of grade> 1

- Patients medically unstable (e.g. unstable diabetes, uncontrolled hypertension or
decompensated heart failure or myocardial infarct within 3 months)

- Gastro duodenal active ulcer

- Hypersensitivity to study drugs

- Treatment with any experimental drug within 30 days prior to or during the study

- Psychological, familial, sociological or geographical location conditions which do
not allow medical monitoring and compliance with study protocol.

- Patients protected by the law or patients placed under protective supervision of
adults