High-precision radiotherapy: where are we going and how do we get there?

In January 2006, physicians with an interest in urologic cancers met to discuss patient care at the 4th Annual Current Problems in Urology Conference. A portion of the meeting was focused on technical issues in prostate cancer radiotherapy. This portion of the meeting sought to answer the questions: where are we going? And how can we get there? Work performed at the Princess Margaret Hospital (PMH) and the London Regional Cancer Program (LRCP) served as the basis for discussion and to present examples of options for implementation of new techniques. The response to the first question reviewed the issue of improved outcomes with dose escalation and the preliminary implementation of hypofractionated treatment. The impact on toxicity was reviewed in detail. The response to the second question revolved around the options available to ensure adequate tumor localization. As dose is increased, the need to localize the prostate accurately has become more important in order to ensure tumor control and to avoid toxicity. Selection of appropriate margins around the prostate is determined by a center's ability to localize the target. Options to localize organs including three-dimensional ultrasound, fiducial markers, megavoltage CT and cone beam CT were discussed. The basic research to enable selection and implementation of these options were presented.