The EORTC QLQ-LC13: a modular supplement to the EORTC core quality of life questionnaire (QLQ-C30) for use in lung cancer clinical trials

The EORTC Study Group on Quality of Life has developed a modular system for assessing the quality of life of cancer patients in clinical trials composed of two basic elements: (1) a core quality of life questionnaire, the EORTC QLQ-C30, covering general aspects of health-related quality of life, and (2) additional disease- or treatment-specific questionnaire modules. Two international field studies were carried out to evaluate the practicality, reliability and validity of the core questionnaire, supplemented by a 13-item lung cancer-specific questionnaire module, the EORTC QLQ-LC13. In this paper, the results of an evaluation of the QLQ-LC13 are reported. The lung cancer questionnaire module comprises both multi-item and single-item measures of lung cancer-associated symptoms (i.e. coughing, haemoptysis, dyspnoea and pain) and side-effects from conventional chemo- and radiotherapy (i.e. hair loss, neuropathy, sore mouth and dysphagia). It was administered to patients with non-resectable lung cancer recruited from 17 countries. In total, 883 and 735 patients, respectively, completed the questionnaire prior to and once during treatment. The symptom measures discriminated clearly between patients differing in performance status. All item scores changed significantly in the expected direction (i.e. lung cancer symptoms decreased and treatment toxicities increased) during treatment. With one exception (problems with a sore mouth), the change of toxicity measures over time was related specifically to either chemo- or radiotherapy. However, the single item on neuropathy did not measure adequately the full range of symptoms. The hypothesised scale structure of the questionnaire was partially supported by the data. The multi-item dyspnoea scale met the minimal standards for reliability (Cronbach alpha coefficient > 0.70), while the pain items did not form a scale with reliability estimates acceptable for group comparisons. In conclusion, the results form international field testing lend support to the EORTC QLQ-LC13 as a clinically valid and useful tool for assessing disease- and treatment-specific symptoms in lung cancer patients participating in clinical trials, when combined with the EORTC core quality of life questionnaire. In a few areas, however, the questionnaire module could benefit from further refinements. In addition, its performance over a longer period of time still needs to be investigated.