Evaluation of novel radiotherapy technologies: what evidence is needed to assess their clinical and cost effectiveness, and how should we get it?

Technical innovations in radiation oncology--eg, intensity-modulated radiotherapy, stereotactic radiotherapy, and particle therapy--can be developed rapidly and introduced into the clinic even when costs associated with their use are much higher than those for conventional radiotherapy. Although clinical benefit is expected on the basis of superior biological and physical characteristics, data for clinical effectiveness of new radiotherapy techniques are scarce. Evidence from randomised clinical trials would be ideal but such studies focus mostly on new drugs. High investment costs and modifications over time make evaluation of novel radiotherapy technologies in clinical trials more complex. Here, we propose an algorithm for evaluation of the clinical and cost effectiveness of novel radiotherapy technologies. We suggest situations when randomised trials might be feasible and the type of trial that should be undertaken when they are not. Furthermore, we discuss the usefulness of dose-distribution models for estimation of expected clinical benefit and for selection of the patients' population with the highest expected benefit. Economic modelling, including the approach of real options analysis, can inform whether implementation of a technology should begin (based on available evidence) or be delayed (until further data are available), and it can indicate the best trial design and required sample size.