International validation of the EORTC QLQ-ELD14 questionnaire for assessment of health-related quality of life elderly patients with cancer

BACKGROUND: Older people represent the majority of cancer patients but their specific needs are often ignored in the development of health-related quality of life (HRQOL) instruments. The European Organisation for Research and Treatment of Cancer (EORTC) QLQ-ELD15 was developed to supplement the EORTC's core questionnaire, the QLQ-C30, for measuring HRQOL in patients aged >70 years in oncology studies. METHODS: Patients (n=518) from 10 countries completed the QLQ-C30, QLQ-ELD15 and a debriefing interview. Eighty two clinically stable patients repeated the questionnaires 1 week later (test–retest analysis) and 107 others, with an expected change in clinical status, repeated the questionnaires 3 months later (response to change analysis, RCA). RESULTS: Information from the debriefing interview, factor analysis and item response theory analysis resulted in the removal of one item (QLQ-ELD15→QLQ-ELD14) and revision of the proposed scale structure to five scales (mobility, worries about others, future worries, maintaining purpose and illness burden) and two single items (joint stiffness and family support). Convergent validity was good. In known-group comparisons, the QLQ-ELD14 differentiated between patients with different disease stage, treatment intention, number of comorbidities, performance status and geriatric screening scores. Test–retest and RCA analyses were equivocal. CONCLUSION: The QLQ-ELD14 is a validated HRQOL questionnaire for cancer patients aged ⩾70 years. Changes in elderly patients' self-reported HRQOL may be related to both cancer evolution and non-clinical events.