Chronic pain after colon cancer surgery: Translation and validation of a scoring system

Objective The aim of this study was to translate and validate the chronic pain score (CP score) in a cohort of colon cancer patients. Chronic pain following colon cancer surgery is still poorly understood, in particular the lack of a validated tool for measuring chronic pain is a major issue as such an instrument is critical for evaluating the incidence and risk factors. The CP score was created using data from Danish rectal cancer patients. Methods Danish colorectal cancer survivors diagnosed between 2001 and 2014 completed the CP score and two quality of life (QoL) measures. Clinical data were obtained from a national database. Convergent validity was investigated by testing the association of the CP score with a single ad hoc QoL item and the EORTC QLQ-C30, and discriminative validity was tested as the score's ability to differentiate between gender and age groups. Sensitivity and specificity were evaluated by determining the ability of the score to identify patients with a major impact of pain on QoL. Results Responses from 7127 colon cancer were included. Convergent validity was confirmed, as the score was associated with both QoL measures (p < 0.001). Moreover, the score could differentiate between males/females and older/younger patients (p < 0.001, respectively), reflecting high discriminative validity. Finally, the score was able to identify patients with a major impact on QoL, with a sensitivity of 87% and specificity of 82%. Conclusion The CP score is a valid tool for measuring chronic pain after colon cancer surgery and should be used to homogenize outcomes in future studies.