The EORTC Quality of Life Study Group has developed a questionnaire for evaluating Quality of Life in international clinical trials: QLQ-C30. The purpose of the present work is to validate the third version of this questionnaire (3.0) for use in Spain. Two hundred and one head and neck cancer patients completed the QLQ-C30 at one or two time points during the treatment and follow-up periods, and a subsample completed the questionnaire on three occasions. Psychometric evaluation of the structure, reliability and validity of the questionnaire was undertaken. The data support the structure and the reliability of the scales. Validity was confirmed in three ways: the interscale correlations are statistically significant and moderate, several scales and items discriminate among groups of patients with different scores on the clinical variables, and some scales reflect significant changes during treatment and the follow-up period. The EORTC QLQ-C30 (version 3.0) is a reliable and valid questionnaire when applied to a sample of Spanish head and neck cancer patients. These results are in line with previous studies.
Copyright 2002 John Wiley & Sons, Ltd.