Prostate cancer may be divided, based on its clinical presentation into localized or advanced disease. For men with clinical T1-T2 prostate cancer, curative therapy or observation are options. For men with advanced disease (T3 or above), hormonal therapy and other palliative treatments are the primary approaches for consideration. Men who have a less than 10 year life expectancy with localized disease, as well as men with less than 5 year life expectancy and asymptomatic advanced disease, expectant management is the optimal initial treatment. Management of localized prostate cancer is a controversial issue, in part because the natural history of localized prostate cancer has been only segmentally elucidated. At present, prostate cancer is the most common cancer diagnosed in men in the United States and the second most common cause of cancer death. The ratio of death rate to incidence suggests that between 20 and 50 percent of men with a clinical diagnosis of prostate cancer will die of the disease. In considering the management of localized prostate cancer, it is important to remember that men with latent, incidental microscopic tumors can only rarely have these cancers detected using today's screening tests of PSA and transrectal ultrasound-guided biopsies (Gardner et al., 1998). Preliminary studies that have evaluated a program of observation or watchful waiting rather than screening with a PSA-based approach suggest that the death rate from prostate cancer will decrease with screening. In addition, the small decrease in prostate cancer death rates associated with the increased screening by PSA (with a five- to seven-year lag period) suggests that earlier screening, detection and treatment of men with prostate cancer may have resulted in saving lives. However, little evidence is available at this point with well-performed randomized studies to confirm that treatment of localized prostate cancer will actually decrease death rates from this disease. In distinction, there is widespread acceptance that breast cancer is an important cause of death in women (Walsh, 1994).
Studies on the natural history of localized prostate cancer have suffered from selection biases, but they allow us some insight into what would occur if patients were not treated with curative intention for localized disease. Almost all of these studies indicate that men with metastatic disease had unrecognized advanced disease at least ten years prior to diagnosis. This is supported by the studies of Carter et al. (1992) where serum PSA levels were followed serially in a number of patients in the Baltimore Longitudinal Study of Aging. Therefore, patients who are candidates for curative local therapy should have a 10-year life expectancy.