Evolution of advanced technologies in prostate cancer radiotherapy.

Conventional treatment options for clinically localized, low-risk prostate cancer include radical prostatectomy, external-beam radiotherapy (EBRT) and low-dose-rate brachytherapy. Advances in image-guided radiotherapy (IGRT) since the 1980s, the development of intensity-modulated radiotherapy (IMRT) during the 1990s and evidence from radiobiological models--which support the use of high doses per fraction--have developed alongside novel advanced radiotherapy modalities that include high-dose-rate brachytherapy (HDR-BT), stereotactic body radiotherapy (SBRT) and proton beam therapy. The relationship between the outcomes of and toxicities experienced by patients with prostate cancer treated with HDR-BT, SBRT and particle-beam therapy should provide urologists and oncologists an understanding of the continually evolving technology in prostate radiotherapy. On the basis of published evidence, conventionally fractionated EBRT with IMRT is considered the standard of care over conventional 3D conformal radiotherapy, whereas HDR-BT boost is an acceptable treatment option for selected patients with intermediate-risk and high-risk prostate cancer. SBRT and proton therapy should not be used for patients (regardless of disease risk group) outside the setting of a clinical trial. Finally, comparative effectiveness research should be conducted to provide a framework for evaluating advanced radiotherapy technologies by comparing the benefits and harms of available therapeutic options to optimize the risk:benefit ratio and improve cost effectiveness.