Translation, cultural adaptation, and validation of the EORTC QLQ-CR29 questionnaire in Serbian patients with colorectal cancer

This study aimed to translate, culturally adapt, and validate the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire for Colorectal Cancer for Serbian patients. The prospective cohort study was conducted at the Clinic for Digestive Surgery, University Clinical Center of Serbia, and included 150 Serbian-speaking colorectal adenocarcinoma patients undergoing colorectal surgery. The translation process involved rigorous forward and backward translations, pilot testing with patients, and statistical analysis for psychometric validation, including internal consistency, reliability, convergent and discriminant validity, concurrent validity, and known-groups validity. Results showed good internal consistency across most scales (Cronbach's alpha values ranging from 0.769 to 0.855), with excellent split-half reliability (0.872). Convergent and discriminant validity analyses confirmed the questionnaire's capacity to measure constructs it was theoretically related. The significant correlations were observed between corresponding scales and items of EORTC QLQ-C30 and EORTC QLQ-CR29 questionnaires. Known-groups analysis demonstrated the tool's ability to distinguish between patient groups based on tumor location, stoma presence, and neoadjuvant therapy. The Serbian version of the EORTC QLQ-CR29 is a reliable and valid instrument for assessing the quality of life in Serbian colorectal cancer patients, reflecting its potential for widespread clinical application.