Common Toxicity Criteria

Common Toxicity Criteria (CTC) is a standardised classification of side effects used in assessing drugs for cancer therapy. Most US and UK drug trials base their observations on this system which has a range of grades from 0-5. Specific conditions and symptoms may have values or descriptive comment for each level, but the general guideline is: 1 - Mild, 2 - Moderate, 3 - Severe, 4 - Life threatening, and 5 - Death. Currently version 3.0 is in use, released in 2003.