Is extended thromboprophylaxis necessary in elective colorectal cancer surgery?

Colorectal cancer surgery carries a high risk of venous thromboembolism (VTE) but the optimal duration of thromboprophylaxis is unknown. The cost-effectiveness of extended prophylaxis is not known in Australasia. The aims of this study were to determine the 30-day incidence of VTE in patients undergoing colorectal cancer surgery, to audit compliance with thromboprophylaxis protocols and to estimate the cost of treating all patients for 28 days with enoxaparin.

Patients undergoing elective colorectal cancer surgery from 2007 to 2009 at the Royal Adelaide and Queen Elizabeth hospitals were identified from a prospective database. Case note review was conducted for patient demographics, VTE risk factors, types of thromboprophylaxis used, complications, readmission rate and VTE rate. Documented compliance with unit VTE protocols was calculated. The cost of treating all patients with enoxaparin as prophylaxis for 28 days was then estimated.

A total of 254 patients were identified. The in-hospital VTE rate was 0.79% (2 out of 254). The post-discharge VTE rate was 0.39% (1 out of 254). Compliance with thromboprophylaxis protocols was excellent. Pharmacological thromboprophylaxis was used in 97% of patients, graduated compression stockings in 84% and pneumatic compression devices in 53%. The estimated cost of extended prophylaxis for all 254 patients was $32,308.80.

We have demonstrated excellent compliance with in-hospital thromboprophylaxis. Hence, we have low VTE rates in-particular, post-discharge VTE. The infrequency of post-discharge VTE means that the cost-effectiveness of extended prophylaxis might be questioned.