Evaluating the Minimal clinically important differences in Quality-of-Life Questionnaires EORTC QLQ-C30 and QLQ-HN35, in head and neck cancer patients according to the European Organization for Research and Treatment of Cancer.

Abstract

Objective Specific and certified quality of life (QoL) Instruments, regarding the EORTC QLQ-C30 and EORTC QLQ-HN35 are used to evaluate the scale of change that is clinically significant in a number of diagnosed and treated head and neck cancer patients. The purpose of the study was to calculate both the statistical and the clinical impact that the disease and the treatment had, in the life of those patients. Materials and Methods The patients answered the EORTC QLQ-C30 and EORTC QLQ-HN35 questionnaires at baseline and in a two-month follow-up period. The calculation of the Minimal clinically important differences (MCID) was feasible via anchor and distribution-based methods both for deterioration and improvement. The anchor used for determining the meaningful change was the Karnofsky Performance (KPS). Results In patients that deteriorated, the symptoms that reached statistical significant meaningful change were greater. Using the KPS anchor, results for meaningful change values in a range from 7.2 (physical functioning) to 16.7 units (Global Health Status) for deterioration were recorded, whereas for improvement, the values ranged from 1.6 (role functioning) to 6.6units (Global Health Status). For both Instruments used, the distribution-based estimates were as good as 0.5 SD. Conclusion The EORTC QLQ-C30 and QLQ-HN35 questionnaires and especially the significant changes on them are important tools when used to evaluate the effect and the outcome of the treatment methods in QoL and also for follow-up reasons. MCIDs are also useful for sample size determination and clinical trial purposes.