Central venous catheter-related thrombosis in cancer patients: what we know and what we need to know

Abstract

To the editor, We read with great interest the paper of Curigliano et al. [1] about the use of low-dose aspirin to prevent venous thromboembolism in breast cancer patients after insertion of central venous catheter (CVC), as it focuses on an unsolved problem in oncology. In the last 20 years, the role of the prophylaxis with warfarin or heparin in the prevention of CVC-associated thrombosis has been widely investigated [2–12]. Although some preliminary experiences suggested a role of low-dose warfarin [2] or low-molecular-weight heparin [3], no advantage of anticoagulants was successively demonstrated when they were compared with placebo [12]. Moreover, no difference between low-dose warfarin and low-molecular-weight heparin was shown in a trial comparing these two different strategies [5]. It follows that, at present, no standard anticoagulant approach is recommended in patients with cancer and central venous catheter [13]. The paper of Curigliano et al. [1] is quite interesting, and the results are impressive, in particular, if they are compared with those reported by the same authors few years ago in a historical control [14]. However, some aspects remain unclear and merit to be discussed. First, are we sure that the evidences of literature are evident enough to recommend further trials investigating the role of different anticoagulants in the prevention of CVC-related thrombosis in cancer patients? Second, are we sure that the evidences of literature are evident enough to recommend a new randomized trial to compare low-dose aspirin with placebo (a comparison vs placebo is much better than vs other anticoagulants) in all cancer patients with CVC? The trial of Curigliano et al. [1] suggests a role of aspirin in the prevention of CVC-related thrombosis, and the recent review of Hovens et al. [15] seems to give a rationale to the use of antiplatelet therapies in the prevention of venous thromboembolism. Adequate comparisons between antiplatelet therapies and low-molecular-weight heparins or vitamin-K antagonists in cancer patients are lacking in literature. However, the efficacy of antiplatelet therapies in surgical and orthopedic patients seems comparable with that of the most used anticoagulant drugs, and the efficacy of anticoagulant drugs in the prevention of CVC-related thrombosis is still questionable [15]. Further comparative trials would probably add little or nothing to the existing inconclusive trials, as the risk differences between patients treated and patients not treated with prophylactic therapies would probably be not enough to recommend the treatment in all cancer patients [12]. In our opinion, further investigations should first be aimed at better defining the thrombotic risk profile of cancer patients with CVC. In a post hoc analysis of the Ethic trial [7], Verso et al. [16] observed that the patients with inadequate position of CVC tip, and left side insertion, had an increased risk of catheterrelated thrombosis. In a prospective trial, Lee et al. [17] identified multiple attempts of catheter insertion, ovarian cancer, and previous CVC insertion as three different independent risk factors of catheter-related thrombosis. Finally, in a cohort trial, Mandala et al. [18] observed a higher risk of catheter-related thrombosis in breast cancer patients with Factor V Leiden heterozygosis than in those Support Care Cancer (2008) 16:311–312 DOI 10.1007/s00520-007-0385-x