Incidence of delayed venous thromboembolic events in patients undergoing abdominal and pelvic surgery for cancer: a systematic review and meta-analysis.

VTE incidence following abdominal cancer surgery varies greatly depending on the study type, with differences largely explained by the method of assessment of VTE. The fact that VTE incidence among retrospective studies was closer to the incidence of symptomatic events (non-screen detected) in the prospective studies, suggests that the screened events were mostly asymptomatic and their clinical significance is unclear.