International phase IV validation study of an EORTC quality of life questionnaire for testicular cancer patients: the EORTC QLQ-TC26

Given the high cure-rate for testicular cancer (TC) and the patients' young age, comprehensive evaluation of health-related quality of life (HRQOL) is an important consideration in this patient population. The EORTC QLQ-TC26 questionnaire module has been developed to supplement the EORTC QLQ-C30 in assessing TC-specific HRQOL in clinical trials and routine clinical practice. This international, multicentre phase IV validation study evaluated the psychometric properties of the new module.

This international, multicentre phase IV validation study enrolled testicular cancer patients from seven European countries. Patients completed the EORTC quality of life core questionnaire EORTC QLQ-C30 and the QLQ-TC26 at two consecutive time points and a debriefing questionnaire regarding the QLQ-TC26 after baseline assessment. Psychometric evaluation included examination of the hypothesized module scale structure, internal consistency and test-retest reliability, known-groups validity, responsiveness to change over time and cross-cultural acceptability.

Data from 313 patients (mean age 38.6, SD 9.5) were analysed. All items exhibited a high completion rate with less than 2.4% missing values except for the sexuality items (up to 8.8%). The confirmatory factor analysis supported the hypothesised scale structure of the QLQ-TC26. Test-retest reliability was good for 8 of 12 scales (intraclass correlation: R t1|t2 ranged from 0.71-0.91) and four scales did not meet the acceptable criteria. Internal consistency was good for all twelve scales (Cronbach alpha = 0.79-0.90), except Communication (alpha = 0.67) and Sexual Functioning (alpha = 0.62). The module was able to distinguish clearly between patients with differing clinical status. Responsiveness to change over time was acceptable.

The EORTC QLQ-TC26 is a valid, reliable and well-accepted condition-specific questionnaire, supplementing the EORTC QLQ-C30, for the assessment of testicular cancer patients' HRQOL in clinical trials.

BMC cancer. 2018 Nov 12*** epublish ***

Monika Sztankay, Neil K Aaronson, Juan I Arraras, Umberto Basso, Uros Bumbasirevic, Fabio Efficace, Johannes M Giesinger, Colin D Johnson, Marieke van Leeuwen, Anne S Oberguggenberger, Roman Sosnowski, Teresa Young, Bernhard Holzner, European Organisation for Research and Treatment of Cancer Quality of Life Group (EORTC QLG)

Medical University of Innsbruck, University Hospital Innsbruck, Psychiatry II, Innsbruck, Austria. ., Division of Psychosocial Research & Epidemiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands., Medical Oncology Department, Hospital of Navarre, Navarre, Spain., Medical Oncology 1, Istituto Oncologico Veneto (IOV) IRCCS, Padova, Italy., Clinic of Urology, Clinical Center of Serbia, University of Belgrade, Belgrade, Serbia., Health Outcomes Research Unit, Italian Group for Adult Hematologic Diseases (GIMEMA), Rome, Italy., Medical University of Innsbruck, University Hospital Innsbruck, Psychiatry II, Innsbruck, Austria., University Surgical Unit, University of Southampton, Southampton University Hospitals, Southampton, UK., Urooncology Department, Maria Sklodowska Curie Memorial Cancer Hospital, Warsaw, Poland., Jackson Macmillan Centre, East & North Hertfordshire NHS Trust including Mount Vernon Cancer Center, Northwood Middlesex, UK.