Urea-creatinine ratio (UCR) predicts the long-term prognosis of colorectal cancer patients after surgery

Background: The muscle mass of tumor patients could significantly affect the prognosis of patients. Urea-creatinine ratio (UCR) was considered related to skeletal muscle catabolism. The objective of this study was to investigate the ability of preoperative UCR to predict postoperative long-term prognosis and to verify the relationship between UCR and muscle mass in colorectal cancer patients. Method: 221 patients with colorectal cancer underwent surgery in the study. Univariate and multivariate logistic analyses were used to determine the risk factors for long-term prognosis. The receiver operating characteristic curve (ROC) was plotted to determine the optimal prognostic cut-off value of UCR. The patients were divided into two groups according to the cut-off value to explore the relationship between UCR and the long-term prognosis of colorectal cancer patients. The same approach was used for subgroup analysis of patients with stage III tumors. Correlation analysis was implemented between the patient's preoperative UCR and the muscle parameters of the L3 cross-section scanned by CT. Results: 221 patients were included from January 2015 to January 2019. Among them, 22 died, and 29 relapsed within 3 years. Multivariate analysis showed that age, BMI, serum creatinine (Scr), UCR, and tumor stage were associated with postoperative overall survival (OS) and relapse-free survival (RFS) (P<0.05). The area under the ROC for predicting 3-year overall survival and recurrence was 0.789 (95%CI: 0.691-0.888, p<0.001), 0.739 (95%CI: 0.581-0.847, p<0.001) in all patients respectively, and in stage III patients were 0.704 (95%CI:0.581-0.826, p=0.007), 0.709 (95%CI:0.595-0.824, p=0.003) respectively. Compared with the UCR low group stratified by a cut-off value of 2.65, the UCR high group had increased risk both for death 0.704 (95%CI:0.581-0.826, p=0.007) and recurrence (0.709 (95%CI:0.595-0.824, p=0.003). In addition, UCR level was significantly associated with skeletal muscle mass (R 2 =0.320, p<0.01). Conclusion: UCR level could effectively predict the long-term prognosis of patients with colorectal cancer after surgery. Patients with UCR above 2.65 had an increased risk of death and tumor recurrence. Moreover, UCR was positively associated with skeletal muscle mass.