Reliability and validity of the Turkish version of the New Cleveland Clinic Colorectal Cancer Quality of Life Questionnaire

Purpose: This study aims to adapt and validate the Cleveland Clinic Colorectal Cancer Quality of Life Questionnaire (CCF-CaQL) in Turkish, addressing the significant need for reliable, language-specific QoL measures for colorectal cancer (CRC) in Turkiye. This effort fills a critical gap in CRC patient care, enhancing both patient-provider communication and disease-specific QoL assessment.

Methods: The CCF-CaQL was translated into Turkish, verified for accuracy, and reviewed for clarity and relevance. Eligible patients who underwent colorectal surgery for cancer between July 2021 and July 2022 from six hospitals completed the CCF-CaQL and SF-36 questionnaires. For analysis, confirmatory factor analysis using Smart PLS 4 and descriptive statistics were employed. The questionnaire's reliability and validity were assessed using Cronbach alpha, composite reliability, and the heterotrait-monotrait (HTMT) ratio, along with multicollinearity checks and factor loadings. Nonparametric resampling was used for precise error and confidence interval calculations, and the Spearman coefficient and split-half method were applied for reliability testing.

Results: In the study involving 244 colorectal cancer patients, confirmatory factor analysis of the CCF-CaQL indicated effective item performance, with one item removed due to lower factor loading. The questionnaire exhibited high internal consistency, evidenced by a Cronbach alpha value of 0.909. Convergent validity was strong, with all average variance extracted (AVE) values exceeding 0.4. Discriminant validity was confirmed with HTMT coefficients below 0.9, and no significant multicollinearity issues were observed (VIF values < 10). Parallel testing with the SF-36 scale demonstrated moderate to very strong correlations, affirming the CCF-CaQL's comparability in measuring quality of life.

Conclusion: The Turkish version of the CCF-CaQL was validated for assessing quality of life in colorectal cancer patients. This validation confirms its reliability and cultural appropriateness for use in Turkiye. The disease-specific nature of the CCF-CaQL makes it a useful tool in clinical and research settings, enhancing patient care by accurately monitoring treatment effects and interventions in the Turkish colorectal cancer patient population.