International validation of the EORTC QLQ-PRT20 module for assessment of quality of life symptoms relating to radiation proctitis: a phase IV study

Georgia K. B. Halkett, Charles Adam Wigley, Samar M Aoun, Maurizio Portaluri, Francesco Tramacere, Lorenzo Livi, Beatrice Detti, Stefano Arcangeli, Jo-Asmund Lund, Are Kristensen, Nathalie McFadden, Arne Grun, Sean Bydder, Irina Sackerer, Elfriede Greimel, Nigel Spry, on behalf of the EORTC Quality of Life Group

Although patients experience radiation proctitis post radiotherapy no internationally tested instruments exist to measure these symptoms. This Phase IV study tested the scale structure, reliability and validity and cross-cultural applicability of the EORTC proctitis module (QLQ-PRT23) in patients who were receiving pelvic radiotherapy. Patients (n = 358) from six countries completed the EORTC QLQ-C30, QLQ-PRT23 and EORTC Quality of Life Group debriefing questions. Clinicians completed the EORTC Radiation Therapy Oncology Group scale. Questionnaires were completed at four time-points. The module's scale structure was examined and validated using standard psychometric analysis techniques. Three items were dropped from the module (QLQ-PRT23 → QLQ-PRT20). Factor analysis identified five factors in the module: bowel control; bloating and gas; emotional function/lifestyle; pain; and leakage. Inter-item correlations were within r = 0.3-0.7. Test-Retest reliability was high. All multi-item scales discriminated between patients showing symptoms and those without symptomology. The module discriminated symptoms from the clinician completed scoring and for age, gender and comorbidities. The EORTC QLQ-PRT20 is designed to be used in addition to the EORTC QLQ-C30 to measure quality of life in patients who receive pelvic radiotherapy. The EORTC QLQ-PRT20 is quick to complete, acceptable to patients, has good content validity and high reliability. Australian and New Zealand Clinical Trials Registry (ANZCTR) ACTRN12609000972224 .