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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.