Daily low-dose aspirin in cancer patients with central venous catheter: new role for an old drug

Abstract

Central venous catheters (CVC) placement increases the risk of blood clots in cancer patients [1–2]. Several randomized trials have evaluated antithrombotic prophylaxis in cancer patients with CVCs with oral anticoagulant or low-molecular-weight heparins (LMWHs) [3–13]. We agree with concerns and questions raised by Dr. Tassinari et al. We can argue that, based on interpretation of the results of contemporary trials, we could not recommend for all patients routine prophylaxis with anticoagulants or LMWH. Cancer patients are receiving increasingly complex chemotherapy regimens in combination with biologic therapies, such as bevacizumab, that can also increase incidence of deep venous thrombosis (DVT) [14]. We believe in the potential efficacy of LMWH but trials with much larger power, with a longer duration of treatment or higher dose would be required. Aspirin can be considered an attractive and safe drug for primary prevention of thrombosis in cancer patients with CVCs. Several trials assessed its efficacy in primary prevention of DVT in normal subjects. A comparison trial designed for high-risk subject (>10 h flight) evaluated impact of prevention with one dose of LMWH (equivalent to 0.1 mL per 10 kg of body weight) versus aspirin (400 mg one dose daily for 3 days, starting 12 h before the beginning of the flight) versus control [15]. Investigators reported 4.8% of subjects with DVT in the control arm, 3.6% in the aspirin arm and no DVT in the LMWH group [15]. Another recent trial investigated the efficacy of long-term aspirin therapy for preventing venous thromboembolism (VTE) in female health care professionals in the Women's Health Study. In this large study, subjects were randomized to aspirin, 100 mg, or placebo on alternate days. The incidence of VTE (per 1,000 person-years) was 1.18 among women randomly assigned to active aspirin, compared with 1.25 among women randomly assigned to placebo. Subgroup analysis for subjects with factor V Leiden, G20210A prothrombin, and MTHFR 677C>T polymorphisms showed a trend versus a beneficial effect from aspirin treatment in this subpopulation [16]. Translating these data into a cancer population, no current studies are so robust to support use of aspirin in the primary prevention of DVT in cancer patients with CVCs. A recent non randomized study in elderly patients with myeloma treated with melphalan, prednisone and lenalidomide demonstrated the efficacy of aspirin in preventing DVT [17]. Another recent meta-analysis evaluated the efficacy and safety of anticoagulation in reducing VTE events in cancer patients with CVCs [18]. Nine randomized controlled trials (RCTs) were included in the meta-analysis. The use of LMWHs in cancer patients with CVC was associated with a trend towards a reduction in symptomatic DVT, but the data did not show any statistically significant effect on mortality, major bleeding or thrombocytopenia. When studies assessing different types of anticoagulants were pooled, symptomatic DVT rates were significantly Support Care Cancer (2008) 16:313–314 DOI 10.1007/s00520-007-0387-8