Validation of the Korean version of the Quality of Life-Cancer Survivors (QOL-CS-K) questionnaire in lymphoma survivors

Purpose The objective of this study was to validate the Korean version of the Quality of Life-Cancer Survivors (QOL-CS-K) in a sample of lymphoma survivors. Materials and Methods We conducted a cross-sectional survey of lymphoma survivors who had survived for at least 24 months since diagnosis. Participants were recruited at the outpatient clinics and at a hospital event in a tertiary hospital in Seoul, Korea. Survivors were asked to complete the QOLCS- K and the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire (EORTC QLQ-C30) questionnaires. To determine test-retest reliability, a second questionnaire was sent to participants who completed the first questionnaire adequately. Exploratory factor analysis and Pearson's correlations were used for evaluating reliability and validity of the QOL-CS-K. Results Among 257 survivors, 245 (95.3%) completed all questionnaires and had no missing data. The mean age of study participants was 52.2 years, 54.9% were men, and the mean time since diagnosis was 4.0±1.6 years. The Cronbach's # for the overall QOL-CS-K was 0.90, and the # coefficients for each subscale ranged from 0.73 to 0.83. The test and retest reliability was 0.88. Moderate correlations were found between comparable subscales of the QOL-CS-K and subscales of the EORTC QLQ-C30 (r=0.51-0.55) except for the spiritual well-being subscale of the QOL-CS-K, which did not correlate with any of the EORTC QLQC30 subscales (-0.08 to 0.16).Conclusion The QOL-CS-K is a reliable and valid scale for measuring the QOL in long-term lymphoma survivors.