Content Validity of Anatomic Site-Specific Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) Item Sets for Assessment of Acute Symptomatic Toxicities in Radiation Oncology

Abstract

To improve assessment of symptomatic toxicity in cancer clinical trials and complement clinician-based toxicity reporting, the US National Cancer Institute developed a measurement system called the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE). The objective of this study was to examine the content validity of PRO-CTCAE in patients undergoing radiation therapy and to establish anatomic site-specific item sets for implementation in cancer research. Patients receiving radiation to the brain, head and neck, breast, thorax, abdomen, or pelvis were recruited during the final week of radiation. Participants described side effects qualitatively and completed anatomic site-specific checklists indicating the presence or absence of symptomatic toxicities drawn from the PRO-CTCAE library. Items endorsed by ≥20% of participants were selected for inclusion. Symptomatic toxicities described qualitatively were content analyzed and summarized. Symptomatic toxicities not reflected in the PRO-CTCAE item library were tabulated. We conducted 389 interviews of patients receiving radiation to the brain (n= 46), head and neck (n = 69), breast (n = 134), thorax (n = 30), abdomen (n = 27), female pelvis (n = 36), or male pelvis (n = 47). Median age was 62 years; 62% were female. The 53 solicited PRO-CTCAE symptoms reflected all reported radiation-induced toxicities with the exception of phlegm/mucus production and mouth/throat pain with swallowing in patients receiving head and neck radiation, eye dryness/irritation in patients undergoing brain radiation, and obstructive urinary symptoms in men receiving pelvic radiation. The PRO-CTCAE items "skin burns" and "pain" require greater specificity to adequately reflect toxicities experienced during radiation. PRO-CTCAE demonstrates strong content validity as a measure of symptomatic toxicities in patients receiving radiation. These results provide empirical support for the definition of site-specific PRO-CTCAE item sets to assess the symptomatic toxicities of radiation therapy. The site-specific PRO-CTCAE item sets developed herein are currently being deployed in our department via an electronic platform to capture treatment-related toxicity.