There are four distinct phases of progression in prostate cancer. They are: Localized disease The cancer is confined to the prostate. The best-case scenario is that prostate cancer is detected early in the disease process, when it is confined to the prostate gland. At this stage there are several treatment options that may completely eliminate the cancer. These include various forms of surgery and radiation, which have cure rates as high as 95% or better, and watchful waiting. Radical prostatectomy (surgery) is the "gold standard" for treatment of localized disease. In patients with early disease, the likelihood of cure is as high as 97%. Also, patients who undergo radical prostatectomy generally live longer. The expected 15-year survival for patients with localized prostate cancer is about 80% following radical prostatectomy, 65% following radiation, and 50 to 60% with watchful waiting. Recurrent disease There are signs the cancer has recurred following localized therapy, but there is no evidence of metastasis. After therapy, there is always a chance the cancer will return, often because cancer cells escaped from the prostate before treatment began. The best way to monitor for recurrence of prostate cancer is to test PSA levels regularly. Some doctors recommend testing more often, but in general all agree that PSA levels should be tested every year. There are also differences of opinion about at what point more treatment should be started once PSA levels start to rise. In deciding when to re-start therapy, men and their doctors can also consider the PSA doubling time and the results of a bone scan. Research published by the Mayo Clinic in the USA in 2007 sheds light on how PSA doubling time can be used to inform treatment decisions. Metastatic disease In this advanced stage, the cancer has spread beyond the prostate. Current treatment options include hormonal therapy (suppression of the male hormones that feed the growth of prostate cancer cells) and chemotherapy. Hormone refractory disease The cancer continues to grow even though the male hormones androgen and testosterone, which help cancer cells grow, have been suppressed with hormone therapy. Treatment options at this stage include chemotherapy which may lengthen life span and lessen the pain caused by cancer spreading to the bones. Not all men progress through all phases. In some cases, the cancer grows so slowly it remains confined to the prostate until the end of the man's life. Other men have their localized cancer completely eliminated with treatments such as surgery or radiation. Unfortunately, there is always a possibility that localized disease may recur, or that the cancer may not be diagnosed until it has spread beyond the prostate. Physicians recommend different treatment approaches based on the state of the disease.