Comparative evaluation of radiation treatments for clinically localized prostate cancer: an updated systematic review.

BACKGROUND: Radiation therapy is one of many treatment options for patients with prostate cancer.
PURPOSE: To update findings on the clinical and biochemical outcomes of radiation therapies for localized prostate cancer. DATA SOURCES: MEDLINE (2007 through March 2011) and the Cochrane Central Register of Controlled Trials (2007 through March 2011). STUDY SELECTION: Published English-language comparative studies involving adults with localized prostate cancer who either had first-line radiation therapy or received no initial treatment. DATA EXTRACTION: 6 researchers extracted information on study design, potential bias, sample characteristics, interventions, and outcomes and rated the strength of overall evidence. Data for each study were extracted by 1 reviewer and confirmed by another. DATA SYNTHESIS: 75 studies (10 randomized, controlled trials [RCTs] and 65 nonrandomized studies) met the inclusion criteria. No RCTs compared radiation therapy with no treatment or no initial treatment. Among the 10 RCTs, 2 compared combinations of radiation therapies, 7 compared doses and fraction sizes of external-beam radiation therapy (EBRT), and 1 compared forms of low-dose rate radiation therapy. Heterogeneous outcomes were analyzed. Overall, moderate-strength evidence consistently showed that a higher EBRT dose was associated with increased rates of long-term biochemical control compared with lower EBRT dose. The body of evidence was rated as insufficient for all other comparisons. LIMITATIONS: Studies inconsistently defined and reported outcomes. Much of the available evidence comes from observational studies with treatment selection biases.
CONCLUSION: A lack of high-quality comparative evidence precludes conclusions about the efficacy of radiation treatments compared with no treatments for localized prostate cancer. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality.