Evaluation of toxicity: clinical issues.

Toxicity criteria used by three of the major cooperative groups are reviewed and discussed. The definition of acceptable toxicity will depend on the extent of disease and the availability of effective therapy. For some forms of toxicity there are adequate early warning signals; for other forms no satisfactory criteria yet exist. Until recently, no attempt had been made to systematically evaluate the quality of the patient's life during and after therapy. We are just now beginning to assess the long-term pathophysiologic changes that occur during and after multimodal therapy. The protocol must include information concerning agent toxicity, criteria for modification of therapy, and time intervals for documentation of toxicity. We must continue to develop therapeutic regimens which control the disease but interfere minimally with the quality of life.