Radiotherapy for prostate cancer: how do we define success?

External beam radiotherapy is widely accepted as one of the therapeutic options in the definitive management of localized prostate cancer. Traditionally the measures of successful outcome have been overall survival and clinical absence of disease. Closer scrutiny using postradiotherapy biopsies and serum prostate specific antigen (PSA) have revealed apparent residual or recurrent disease more frequently than previously suspected clinically. This article will deal with each of these outcome parameters to establish a clinically useful perspective for practicing urologists.