In cancer clinical trials, adverse events (AEs) are collected and reported using the US National Cancer Institute’s (NCI’s) Common Terminology Criteria for Adverse Events (CTCAE).¹ The CTCAE is a library of items representing 790 discrete AEs, each graded using an ordinal severity scale.² Approximately 10% of AEs in the CTCAE are symptoms (eg, nausea, sensory neuropathy), which in trials have historically been reported by clinical investigators.³ However, there is empirical evidence that collection of this information directly from patients improves the precision and reliability of symptomatic AE detection in trials^4-9and is feasible.^10,11 Moreover, there is substantial evidence that clinical investigators may miss up to half of patients’ symptomatic AEs.^5,6,12,13

Context. In 2006, the United States Food and Drug Administration (FDA) released a draft Guidance for Industry on the use of patient-reported outcomes