Prostate Cancer Treatment (PDQ®): Treatment - Health Professional Information [NCI] - General Information About Prostate Cancer
Carcinoma of the prostate is predominantly a tumor of older men: the median age at diagnosis is 72 years. Prostate cancer may be cured when localized, and it frequently responds to treatment when widespread. The rate of tumor growth varies from very slow to moderately rapid, and some patients may have prolonged survival even after the cancer has metastasized to distant sites, such as bone. The 5-year relative survival rate for men diagnosed in the United States from 2001 to 2007 with local or regional disease was 100%, and the rate for distant disease was 28.7%; a 99% survival rate was observed for all stages combined.[SEER Stat Fact Sheets: Prostate] The approach to treatment is influenced by age and coexisting medical problems. Side effects of various forms of treatment should be considered in selecting appropriate management.
Many patients—especially those with localized tumors—may die of other illnesses without ever having suffered disability from the cancer, even if managed conservatively without an attempt at curative therapy.[3,4] In part, these favorable outcomes are likely the result of widespread screening with the prostate-specific antigen (PSA) test, which can identify patients with asymptomatic tumors that have little or no lethal potential. There is a large number of these clinically indolent tumors, estimated from autopsy series of men dying of causes unrelated to prostate cancer to be in the range of 30% to 70% of men older than 60 years.
Because diagnostic methods have changed over time, any analysis of survival after treatment of prostate cancer and comparison of the various treatment strategies is complicated by the evidence of increasing diagnosis of nonlethal tumors. Nonrandomized comparisons of treatments may be confounded not only by patient selection factors but also by time trends.
For example, a population-based study in Sweden showed that, from 1960 to the late 1980s, before the use of PSA for screening purposes, long-term relative survival rates after the diagnosis of prostate cancer improved substantially as more sensitive methods of diagnosis were introduced. This occurred despite the use of watchful waiting or active surveillance or palliative hormonal treatment as the most common treatment strategies for localized prostate cancer during the entire era (<150 radical prostatectomies per year were performed in Sweden during the late 1980s). The investigators estimated that, if all prostate cancers diagnosed between 1960 and 1964 were of the lethal variety, then at least 33% of cancers diagnosed between 1980 and 1984 were of the nonlethal variety.[Level of evidence: 3iB] With the advent of PSA screening as the most common method of detection in the United States, the ability to diagnose nonlethal prostate cancers has further increased.
Another issue complicating comparisons of outcomes among nonconcurrent series of patients is the possibility of changes in criteria for the histologic diagnosis of prostate cancer. This phenomenon creates a statistical artifact that can produce a false sense of therapeutic accomplishment and may also lead to more aggressive therapy.