Abstract
Constipation is a common and distressing side effect among cancer patients undergoing treatment, significantly affecting their quality of life and treatment adherence. Accurate assessment is essential for timely and effective management. This study aimed to adapt the Constipation Assessment Scale into Turkish and evaluate its validity and reliability among Turkish cancer patients. This methodological study was conducted with 100 cancer patients receiving treatment in a public hospital in İzmir, Turkey. The adaptation process included translation, back-translation, expert review, and pilot testing. Content validity was assessed using the Content Validity Index, and construct validity was evaluated through confirmatory factor analysis. Reliability was tested using Cronbach alpha, item-total correlations, and test-retest analysis. The Content Validity Index was 1.00, indicating excellent content validity. Confirmatory factor analysis results supported the scale's construct validity with acceptable model fit indices. Cronbach alpha was 0.926, demonstrating high internal consistency. Test-retest analysis showed strong stability over time, with high intraclass correlation coefficients and no significant differences between administrations. The Turkish version of the Constipation Assessment Scale is a valid and reliable tool for assessing constipation in cancer patients. Its use in clinical practice can enhance symptom monitoring and support timely interventions in oncology care.