Purpose: The aim of this clinical trail is to evaluate the effectiveness of Zoledronate (Zometa) combined with Estramustine and Docetaxel (Taxotere) in the treatment of patients with hormone-refractory prostate cancer.

Hormone refractory prostate cancer refers to advanced disease in which the patient no longer responds to conventional hormonal treatment. When hormone therapy is no longer successful, chemotherapy is a treatment option. However, current single-agent treatment has shown to have limited benefit. In this clinical trail, investigators are evaluating the effectiveness of Zoledronate(Zometa) combined with Estramustine and Docetaxel (Taxotere) in the treatment of patients with hormone refractory prostate cancer. Zometa is a bisphosphonate, and may reduce or delay skeletal complications caused by bone metastases. Estramustine and Taxotere are chemotherapy drugs that have shown activity in hormone refractory prostate cancer. Eligible patients will be randomized to receive Estramustine and Docetaxel (Taxotere) in combination with Zometa or Zometa given alone.

All patients must have a histologic diagnosis of hormone-refractory adenocarcinoma of the prostate, and hormone refractory disease must be demonstrated by the appearance of new lesions on bone or CT scan and/or a rising PSA value. (No evidence of brain metastasis or untreated spinal cord compression.)

Patients on total androgen suppression therapy must undergo nonsteroidal antiandrogen withdrawal and demonstrate a rising PSA 4 weeks after withdrawal from flutamide and 6 weeks after withdrawal from bicalutamide.

Patient must not be undergoing current chemotherapy, biologic therapy, other investigational or alternative anti-cancer directed therapy or radiation therapy.

Prior radiation therapy must have completed more than 4 weeks prior to registration.

Patients may not have received prior taxane-based cytotoxic chemotherapy for hormone refractory disease.