TEST-RETEST STUDY OF THE EUROPEAN ORGANIZATION FOR RESEARCH AND TREATMENT OF CANCER CORE QUALITY-OF-LIFE QUESTIONNAIRE

Purpose: The European Organization for Research and Treatment of Cance r Core Quality of Life Questionnaire (EORTC QLQ-C30) is a well-validat ed instrument that assesses health-related quality of life (HRQOL) in cancer patients, It is used in cancer clinical trials in Europe, Canad a, and the United States, and has demonstrated high reliability and va lidity in different groups of cancer patients, Despite thorough testin g of reliability and validity, we have not identified any reports on i fs test/retest reliability; thus, a test/retest study was performed at the Norwegian Radium Hospital (NRH). Materials and Methods: Cancer pa tients from the outpatient clinic who were off treatment for greater t han or equal to 3 months were eligible for the study. The EORTC QLQ-C3 0 was given to the patients when they presented for their visit, The s econd questionnaire was received by the patients 4 days later, Of 291 eligible patients, 270 (93%) agreed to participate and 190 (73%) compl eted both questionnaires. Results: The test/retest reliability measure d by Pearson's correlation coefficient was high for all functional sca les, with a range from .82 for cognitive and role function to .91 for physical function, The r value for global HRQOL was .85. For the sympt om scales-nausea/vomiting, fatigue, and pain-the coefficients were .63 , .83, and .86, respectively, The single-item coefficients ranged from .72 for diarrhea to .84 for financial impact, The Spearman rank corre lation was in the same range for all dimensions. Conclusion: The EORTC QLQ-C30 seems to yield high test/retest reliability in patients with various cancer diagnoses whose condition is not expected to change dur ing the time of measurement. (C) 1995 by American Society of Clinical Oncology.