The standard lexicon for reporting adverse events in NCI-sponsored clinical trials is the Common Terminology Criteria for Adverse Events (CTCAE). Currently, adverse events are reported by clinicians, yet evidence suggests that compared to patient-report, clinicians may underestimate symptom onset and severity.

A clinical trials planning meeting in 2007 suggested that adverse event reporting would be strengthened by the systematic inclusion of the patient perspective captured through the use of well-validated patient-reported outcomes (PRO). Developed to complement standard toxicity reporting using the CTCAE, the US National Cancer Institute's PRO-CTCAE is a new patient-reported outcome measurement system that elicits various attributes of 78 symptomatic treatment toxicities that can be meaningfully reported from the patient perspective.

Capturing symptomatic toxicity can be challenging since the onset and character of adverse events varies within and across trials based on the distinct, on- and off-target toxicity profile of a specific therapy. Thus the approach to measuring symptomatic toxicity must be flexible within and across studies.

The National Cancer Institute's PRO-CTCAE measurement system was developed as a companion to the Common Terminology Criteria for Adverse Events (CTCAE), the standard lexicon for adverse event reporting in cancer trials. It is not intended to be used as a stand-alone patient-reported outcome, or to be included in every study. The current standard for grading and reporting all AEs in cancer clinical trials, including symptomatic AEs, is clinician grading using the CTCAE.

The PRO-CTCAE measurement system includes an item library of 124 discrete items representing 78 symptomatic toxicities drawn from the CTCAE. As such, it provides a systematic yet flexible approach to capture symptomatic adverse events in trials of new cancer therapies.