Many patients enter cancer clinical trials with baseline symptoms. Notably, the current clinician reporting mechanism for symptomatic adverse events (AEs) via the Common Terminology Criteria for Adverse Events (CTCAE) does not formally distinguish between symptoms present at baseline vs those that develop during a trial. Therefore, AE estimation in clinical trials may include symptoms that predate trial entry. This raises concern that the cumulative incidence of patient-reported AEs may be high, particularly if preexisting symptoms related to other causes (eg, comorbidities, prior treatment) are attributed to study drugs
