Thromboprophylaxis in cancer patients with central venous catheters. A systematic review and meta-analysis.

It was the aim of the review to determine the risks and benefits of primary thromboprophylaxis with anticoagulants in cancer patients with central venous devices. Medline, Central and Google Scholar databases were searched for randomized controlled trials (RCTs) in June 2006. Two reviewers extracted data and appraised the quality of RCTs. Results were expressed as relative risk (RR) with 95% confidence intervals (CI) using random effects model for the outcomes of catheter-related thrombosis, bleeding and thrombocytopenia. Eight RCTs (1,428 patients) were included. There was no statistically significant difference in the risk of catheter-related thrombosis for the use of warfarin versus placebo (3 trials, 425 patients, RR 0.75, 95% CI 0.24-2.35, p = 0.63), heparin versus placebo (4 trials, 886 patients, RR 0.46 95% CI 0.18-1.20, p = 0.06) or warfarin, unfractionated heparin or low-molecular-weight heparin versus placebo (7 trials, 1,311 patients, RR 0.59, 95% CI 0.31-1.13, p = 0.11). Substantial statistical heterogeneity was noted among these trials (I(2) > 50%). The use of anticoagulants showed no statistically significant difference in the risk of overall bleeding (5 trials, 1,193 patients, RR 1.24, 95% CI 0.84-1.82, p = 0.28), and thrombocytopenia for heparin versus placebo (4 trials, 958 patients, RR 0.85, 95% CI 0.49, 1.46, p = 0.55) without any statistical heterogeneity (I(2) = 0%). In cancer patients with central venous devices, thromboprophylaxis has no significant effect on the risk of catheter related thrombosis or bleeding. The use of primary thromboprophylaxis in cancer patients with central venous catheters while not causing any harm provides no benefit.