Context: To improve precision and accuracy in the capture of symptomatic adverse events (AEs) by self-report, the U.S. National Cancer Institute has developed a library of 124 patient-reported outcome (PRO) items reflecting 78 symptomatic AEs drawn from the Common Terminology Criteria for Adverse Events (CTCAE). The PRO-CTCAE™ item library has been translated and linguistically validated in the Korean language.

Objectives: The aim of this study was to examine the psychometric properties of PRO-CTCAE-Korean.

Methods: PRO-CTCAE-Korean and the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire Core 30 (QLQ-C30) were administered to 1358 Korean-speaking individuals receiving treatment for cancer at two medical centers in Korea (mean age 55.1 years; SD ±11.9; 60% females; and 61% high school education or less). A subset of 82 study participants completed the same two measures on a second occasion approximately three days later.

Results: Correlations between PRO-CTCAE-Korean and conceptually relevant QLQ-C30 items were all greater than r = 0.30 except for headache severity. Most PRO-CTCAE-Korean items correlated at least moderately with QLQ-C30 summary scores. Monotonically decreasing total QLQ-C30 scores were observed across worsening levels of symptom frequency, severity, and interference (all P < 0.01), indicating that PRO-CTCAE-Korean response choices are well comprehended, and that PRO-CTCAE-Korean discriminates respondents with different levels of symptom burden. PRO-CTCAE-Korean also demonstrated generally acceptable to good reliability (88% of items intraclass correlation coefficient >0.50).

Conclusion: PRO-CTCAE-Korean is a reliable and valid instrument to capture symptomatic AEs by self-report in patients on cancer clinical trials.