Prostate cancer is the most common male malignancy in the US. In the year 2000 there were approximately 180 400 new cases of prostate cancer with approximately 31 900 deaths. Most patients present with localized disease and treatment choices include surgery, radiation (external beam or brachytherapy), or observation. It is well recognized that a minority of patients will develop metastatic disease after definitive local therapy or present with metastatic disease. Some of these patients will have a very indolent course and not die of prostate cancer, whereas others will have aggressive disease that will metastasize from the prostate gland and be the cause of the patient's death. Progression is often first manifest by an increasing prostate-specific antigen (PSA). The mere presence of an elevated PSA after definitive local therapy does not portend a poor outlook. For example, in one series of 315 patients who underwent a prostatectomy it was noted that the median survival was more than 10 years if the PSA rose 2 years after the surgery, took longer than 10 months to double and the Gleason's score was 7 or less.

However, survival is shorter once patients have visible metastases on radiographic imaging and/or symptomatic lesions. Standard initial therapy for metastatic disease consists of androgen ablation. Dr. Huggins won the Nobel prize in medicine for his discovery that prostatic epithelium will undergo atrophy with withdrawal of androgen stimulation.