External validation of four venous thromboembolism risk assessment models after colorectal cancer surgery: a retrospective study.

BACKGROUND: Caprini score, the most commonly used assessment tool for predicting postoperative venous thromboembolism (VTE) risk has shown poor predictive value in colorectal cancer surgery. Recent risk assessment models (RAMs) Sir-Run-Run-Shaw VTE RAM, Risk of Venous Thromboembolism Algorithm (RVTA) score, and Colorectal Cancer - Venous Thromboembolism (CRC-VTE) score, which were specific for colorectal cancer, were developed and had good VTE predictive performance. We sought to externally validate for their generalizability and accuracy in Chinese patients undergoing colorectal cancer surgery. MATERIALS AND METHODS: A retrospective analysis was conducted to predict the 6-month postoperative VTE risk in patients undergoing colorectal cancer surgery from January 2020 to December 2023. Demographic characteristics, clinical data, and 6-month postoperative VTE status of the patients were collected based on Sir-Run-Run-Shaw VTE RAM, RVTA score, CRC-VTE score, and Caprini score. We estimated the four VTE RAMs' discrimination of 6-month postoperative VTE risk by using the area under the receiver operating characteristic curve (AUROC). Calibration plots, Hosmer-Lemeshow test, and decision curve analysis were also explored to assess the predictive performance of the four VTE RAMs. RESULTS: A total of 323 patients were included. The median age of our cohort was 66 years (range, 58-73 years), and 182 (56.3%) patients were male. VTE occurred in 68 (21.1%) cases within 6 months after operation, with 5 cases of pulmonary embolism and 63 cases of deep vein thrombosis, of which 45 (66.2%) cases experienced VTE within 4 weeks after operation. Sir-Run-Run-Shaw VTE RAM, RVTA score, CRC-VTE score and Caprini score demonstrated possibly helpful discrimination, with AUCs of 0.691 (95%CI: 0.624-0.758), 0.638 (95%CI: 0.564-0.713), 0.728 (95%CI: 0.663-0.793), and 0.661 (95%CI: 0.596-0.725), respectively. The Hosmer-Lemeshow test indicated a lack of fit for Sir-Run-Run-Shaw VTE RAM, RVTA score, and CRC-VTE score (P < 0.05). Furthermore, decision curve analysis revealed that CRC-VTE score provided greater net benefits than the other VTE RAMs. CONCLUSION: External validation of the four VTE RAMs for predicting postoperative VTE in a real-world cohort of colorectal cancer patients showed that CRC-VTE score outperformed the other VTE RAMs. It can help clinicians identify patients with high risk of VTE, thereby facilitating timely prophylactic interventions and close monitoring.