Abstract
METHODS
Thyroid cancer patients under active treatment were contacted three times (t1: before treatment, t2: six weeks after t1, t3: six months after t2). They completed the EORTC QLQ-C30, the EORTC QLQ-THY34, and the Subjective Significance Questionnaire, indicating experienced change from the previous time point in five QoL domains. The Minimal Important Change (MIC) was established based on logistic regression models. Additionally, Minimal Detectable Change (MDC) was computed using 0.5 standard deviation and standard error of the measurement.
CONCLUSIONS
No single MIC or MDC can be applied to all EORTC QLQ-THY34 scales, and the MIC for improvement are generally smaller than those for deterioration. The estimates can be used in research and clinical practice to interpret QoL scores in thyroid cancer patients.
RESULTS
Altogether, 275 patients from 15 countries participated. MIC for deterioration and improvement were respectively 5 and 1 for exhaustion, 13 and 7 for voice problems, 11 and 2 for tingling sensation, 12 and 11 for altered temperature tolerance, and 2 and 2 for overall QoL. The MDC estimates for deterioration ranged from 7 (physical functioning) to 25 (dyspnoea); for improvement, it ranged from 7 (physical functioning) to 15, for appetite loss, cramps, and altered temperature tolerance.
PURPOSE
The European Organisation for Research and Treatment of Cancer Thyroid Cancer Quality of Life (QoL) Module (EORTC QLQ-THY34) is a valid tool to assess QoL in this patient population. The present study established estimates for score interpretation thresholds for this instrument when using it with thyroid cancer patients.