Common Terminology Criteria for Adverse Events

The Common Terminology Criteria for Adverse Events (CTCAE), formerly called the Common Toxicity Criteria (CTC or NCI-CTC), are a set of criteria for the standardized classification of adverse effects of drugs used in cancer therapy. The CTCAE system is a product of the US National Cancer Institute (NCI). The current version 4.03 was released in 2010. Many clinical trials, now extending beyond oncology, encode their observations based on the CTCAE system. It uses a range of grades from 1 to 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 5 - Death

See Reference for full details on the current criteria.