Extended venous thromboembolism prophylaxis after colorectal cancer surgery: the current state of the evidence.

There is level one evidence to support combined mechanical and chemical thromboprophylaxis for 7-10 days after colorectal cancer surgery, but there remains a paucity of data to support extended prophylaxis after discharge. The aim of this clinical review is to summarise the currently available evidence for extended venous thromboprophylaxis after elective colorectal cancer surgery. Clinical review of the major clinical guidelines and published clinical data evaluating extended venous thromboprophylaxis after elective colorectal cancer surgery. Five major guideline recommendations are outlined, and the results of the five published randomised controlled trials are summarised and reviewed with a specific focus on the efficacy and cost-effectiveness of extended heparin prophylaxis to prevent clinically relevant post-operative venous thromboembolism (VTE) after colorectal cancer surgery. Extended VTE prophylaxis after colorectal cancer surgery reduces the incidence of asymptomatic screen detected deep venous thrombosis (DVT) only, with no demonstrable reduction in symptomatic DVT, symptomatic PE, or VTE related death. Evidence for cost-effectiveness is limited. As the incidence of clinical VTE is very low in this patient subgroup overall, future research should be focused on higher risk patient subgroups in whom a reduction in VTE may be both more demonstrable and clinically relevant.