The evolution and application of toxicity criteria

The assessment and reporting of toxicity plays a central role in oncology. The foundation of toxicity reporting is the toxicity criteria system. Multiple systems have been developed and have evolved substantially since first introduced more than 20 years ago. The wide adoption of a standardized criteria system can facilitate comparison between institutions and clinical trials. The Common Toxicity Criteria (CTC) system was revised and expanded substantially in 1997 and now includes acute radiation criteria as part of multimodality grading. In contrast to the progress made in standardizing acute effects, the current use of multiple late effects grading systems by different groups hinders comparability of clinical trials, impedes the development of toxicity interventions, and encumbers the proper recognition and reporting of late effects. Just as the revised CTC has provided a new common standard for the grading of acute effects, a similar effort is needed in the late effects area. The creation of a unified late effects system is under active development.