Background: Thyroid cancer and its treatments affect quality of life (QoL) across a variety of domains. The EORTC Quality of Life Group therefore developed a module specifically for this group of patients. This development started in 2013 with the identification of potential QoL issues and then testing their relevance to patients and health care providers (phase I and II). In 2015 and 2016, the provisional module was pilot tested (phase III) among 182 thyroid cancer patients. Now phase III has been successfully completed, resulting in the preliminary EORTC QLQ-THY34, the final validation (phase IV) is performed.
Objectives: The aim of the present study is to validate the EORTC QLQ-THY34 in a large international field study and to investigate the psychometric properties of its scales.
We will investigate
– cross-cultural applicability and acceptability
– scale structure
– reliability, including test-retest and internal consistency
– validity, including construct, divergent and convergent validity
– sensitivity to change, responsiveness
– minimally important difference
– cross-cultural consistency of psychometric properties
Procedures: The EORTC QLQ-THY34 will be administered to two groups of patients with thyroid cancer. Patients in Group 1 will be approached three times to measure sensitivity to change. The data collection will take place before treatment starts (t1), 6 weeks after the first day of initial treatment (t2), and 6 months after t2 (t3). Patients in Group 2 will complete the questionnaires once (t1) (a minimum of 24 months post diagnosis) and a second time 1 week later (t2) to measure test-retest reliability. The patients will be asked to complete several questionnaires at each measurement point including the EORTC QLQ-C30, the EORTC QLQ-THY34, and the EQ-5D. At t1, they will also be asked to complete a debriefing questionnaire. In group 1, they will indicate their subjective change in QoL using the Subjective Significance Questionnaire (SSQ) at t2 and t3.
Sample size: Group 1: n=300, Group 2: n=100
The study protocol for phase IV has been developed and the first patients are enrolled.
We expect to complete enrolment by September 2019.
We create a questionnaire for patients with thyroid cancer. When they complete this questionnaire, they can tell their doctor how their quality of life currently is. This is important for clinical studies because responses from different patients can then be combined easily, and the voice of the patients is heard.