Incidence and Risk Factors of Venous Thromboembolism Following Hepatectomy for Colorectal Metastases: A Population-Based Retrospective Cohort Study

Background Incidence of venous thromboembolism (VTE) following hepatectomy for colorectal cancer (CRC) metastases is unclear. These patients may represent a vulnerable population due to increased tumour burden. We aim to identify the risk of VTE development in routine clinical practice among patients with resected CRC liver metastases, the associated risk factors, and its impact on survival. Methods We conducted a population-based retrospective cohort study of Ontario patients undergoing hepatectomy for CRC metastases between 2002 and 2009 using linked universal healthcare databases. Multivariable logistic regression was used to estimate the association between patient characteristics and VTE risk at 30 and 90-days after surgery. Cox proportional-hazards regression was used to estimate the association between VTE and adjusted cancer specific (CSS) and overall survival (OS). Results 1310 patients were included with a mean age of 63 +/- 11. 62% were male. 51% had one metastatic deposit. Major hepatectomy occurred in 64%. VTE occurred in 4% within 90 days of liver resection. Only longer length of stay was associated with VTE development (OR 6.88 (2.57-18.43), p <0.001 for 15-21 days versus 0-7 days). 38% of VTEs were diagnosed after discharge, comprising 1.52% of the total cohort. VTE was not associated with inferior CSS or OS. Conclusions Risk of VTE development in this population is similar to those undergoing hepatectomy for other indications, and to the risk following other cancer site resections where post-operative extended VTE prophylaxis is currently recommended. The number of VTEs occurring after discharge suggests there may be a role for extended VTE prophylaxis.