Abstract
Background Obstructive colorectal cancer (OCRC) mostly accompanied with nutritional deficiencies and severe local inflammation that deteriorated sarcopenia, negatively impact on the long-term survival. Although sarcopenia has been investigated in other malignancies, its prognostic role in OCRC remains poorly characterized. Here, we sought to construct a preoperative prognostic model that integrates sarcopenia status with clinical features to improve prediction of predicting 3-year overall survival (OS) and disease-free survival (DFS) in OCRC patients. Methods We retrospectively reviewed the records of 109 patients who underwent curative resection for OCRC. Skeletal muscle index (SMI) was quantified from preoperative CT scans, and the optimal thresholds for diagnosing sarcopenia was determined using X-tile software. Cox proportional hazards models were applied to determine prognostic factors, which were integrated into a composite risk score. The predictive accuracy of the scoring system was assessed using the area under the receiver operating characteristic (ROC) curve (AUC). Results Among the cohort, 49 (45.0%) were diagnosed with sarcopenia. Sarcopenia significantly correlated with poorer OS and DFS and was independently associated with worse outcomes in multivariable analysis (OS: Hazard ratio [HR] = 2.034, 95% confidence interval [CI] 1.810–3.800, p = 0.026; DFS: HR = 1.811, CI 1.011–3.245, p = 0.046). The final model, incorporating sarcopenia, cT stage, and serum CEA level, effectively separated patients into subgroups with distinct survival outcomes. Forest plot analysis using the Cox proportional hazards model demonstrated the high-risk group exhibited significantly elevated risks compared to the low-risk group, with hazard ratios of 7.098 (95% CI 2.390–21.078, P < 0.001) for OS and 9.385 (95% CI 2.783–31.643, P < 0.001) for DFS. The scoring system achieved acceptable predictive performance, with AUCs of 0.736 for OS and 0.708 for DFS. Conclusions Preoperative sarcopenia was shown to negatively influence postoperative survival in OCRC patients. A prognostic scoring system incorporating preoperative sarcopenia, cT stage, and CEA level provided reliable prognostic stratification and may assist in individualized risk assessment and clinical decision-making. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12893-025-03259-z.