Linguistic Validation of the US National Cancer Institute’s Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events in Korean

PURPOSE: The aim of this study was to translate and linguistically validate a Korean-language version of the US National Cancer Institute’s Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE). METHODS: All 124 PRO-CTCAE items were translated into Korean (PRO-CTCAE-Korean) using International Society for Pharmacoeconomics and Outcomes Research best practices and linguistically validated in a diverse sample of patients undergoing cancer treatment (n = 120) to determine whether the Korean translation captured the original concepts. During the cognitive interviews, participants first completed approximately 60 PRO-CTCAE-Korean questions and were then interviewed to evaluate the conceptual equivalence of the translation to the original PRO-CTCAE English-language source. Interview probes addressed comprehension, clarity, and ease of judgement. Three rounds of interviews were conducted. Items that met the a priori threshold of 10% or more of respondents with comprehension difficulties were considered for rephrasing and retesting. RESULTS: A majority of PRO-CTCAE-Korean items were well comprehended in round 1; 14 items posed comprehension difficulties for at least 10% of respondents in round 1. Four symptom terms (mouth and throat sores, feeling like nothing could cheer you up, frequent urination, and pain, swelling, redness at drug injection or intravenous insertion site) were revised and retested in rounds 2 and 3. For the other 10 symptom terms, no suitable alternative phrasing was identified, and the terms were retested in rounds 2 and 3. After rounds 2 and 3, no item presented difficulties in 20% or more of participants. CONCLUSION: PRO-CTCAE-Korean has been linguistically validated for use in Korean-speaking populations. Quantitative evaluation of this new measure to establish its measurement properties and responsiveness in Korean speakers undergoing cancer treatment is in progress.