Role of Extended Thromboprophylaxis After Abdominal and Pelvic Surgery in Cancer Patients: A Systematic Review and Meta-Analysis

Abdominopelvic cancer surgery increases the risk of postoperative venous thromboembolism (VTE). Low-molecular-weight heparin (LMWH) thromboprophylaxis is recommended, and the role of extended thromboprophylaxis (ETP) is controversial. We performed a systematic review to determine the effect of ETP on deep vein thrombosis (DVT), pulmonary embolism (PE), major bleeding, and all-cause mortality after abdominal or pelvic cancer surgery. A search of the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials was undertaken, and studies were included if they compared extended duration (2-6 weeks) with conventional duration of thromboprophylaxis (2 weeks or less) after cancer surgery. Pooled relative risk (RR) was estimated using a random effects model. Seven randomized and prospective studies were included, comprising 4807 adult patients. ETP was associated with a significantly reduced incidence of all VTEs [2.6 vs. 5.6 %; RR 0.44, 95 % confidence interval (CI) 0.28-0.70, number needed to treat (NNT) = 39] and proximal DVT (1.4 vs. 2.8 %; RR 0.46, 95 % CI 0.23-0.91, NNT = 71). There was no statistically significant difference in the incidence of symptomatic PE (0.8 vs. 1.3 %; RR 0.56, 95 % CI 0.23-1.40), major bleeding (1.8 vs. 1.0 %; RR 1.19, 95 % CI 0.47-2.97), and all-cause mortality (4.2 vs. 3.6 %; RR 0.79, 95 % CI 0.47-1.33). None of the outcomes differed if randomized trials were analyzed independently. ETP after abdominal or pelvic surgery for cancer significantly decreased the incidence of all VTEs and proximal DVTs, but had no impact on symptomatic PE, major bleeding, or 3-month mortality. ETP should be routinely considered in the setting of abdominal and pelvic surgery for cancer patients.