Understanding the toxicity of cancer immunotherapies: Use of patient-reported outcomes

Immunotherapy has transformed the treatment of various cancers by strengthening suppressed immune systems for antitumor effects. However, altering the immune balance also produces unconventional adverse events (AEs) that are collectively referred to as immune-related AEs. These AEs, which can be thought of as symptomatic toxicities, are typically reported via tabulation of AEs from the National Cancer Institute’s Common Terminology Criteria for AEs. These AEs are reported by clinicians. However, it is well known that clinicians’ reports of their patients’ symptoms are underestimates and in some cases may not be consistent with patients’ reports. The symptomatic adverse effects of immunotherapy are best reported by the patients themselves, known as patient-reported outcomes (PROs). This review describes the use of PROs specifically pertaining to symptom burden in cancer patients. The review also discusses challenges in the use of PROs in patients undergoing immunotherapy and provides recommendations for future research.