Philip S. Wells, MD
Are anticoagulants effective for preventing and treating venous thromboembolism (VTE) in patients with cancer?
MEDLINE, EMBASE/Excerpta Medica, Cancerlit, Cochrane Library, and National Guideline Clearing House (to 2006); conference proceedings (2003 to 2006); reference lists; and experts.
Randomized controlled trials that evaluated low-molecular-weight heparin (LMWH), unfractionated heparin, or an oral vitamin K antagonist (VKA) in adults with cancer and had an appropriate control group as well as a method of regular patient follow-up, VTE or death as an a priori outcome, and objective confirmation of VTE. Studies of VTE prophylaxis related to indwelling catheters were excluded. The number of studies that met the selection criteria was not stated.
Survival, VTE including deep venous thrombosis and pulmonary embolism, and bleeding complications.
The guideline was based, in part, on the review described above; data from trials of cancer patients only are reported here. VTE prevention: 3 trials of ambulatory patients having chemotherapy had inconsistent results (Table); major bleeding at 6 months was reported in 2 trials of LMWH vs placebo (n = 353, 1.7% vs 0%; n = 547, 3.7% vs 2.2%).VTE recurrence: LMWH reduced recurrence of VTE more than treatments including a VKA (Table), major bleeding rates did not differ at 6 months in 1 trial (n = 672, 6% vs 4%), and hemorrhagic deaths occurred in 0 vs 6 patients in another (n = 146). Survival: In a meta-analysis of 11 trials in patients with no VTE, 1-year mortality was decreased with anticoagulants (relative risk reduction 9%, 95% CI 3 to 15); control treatments were not reported. Major bleeding was more common with anticoagulants and was increased with warfarin over LMWH (P < 0.001).
Limited data are available to evaluate the effectiveness of anticoagulation as prophylaxis or therapy for cancer patients.
Anticoagulant prophylaxis and therapy for venous thromboembolism (VTE) in patients with cancer*
*Chemo = chemotherapy; LMWH = low-molecular-weight heparin; NS = not significant; UFH = unfractionated heparin; VKA = vitamin K antagonist; other abbreviations defined in Glossary. RRR and NNT reported in article for ambulatory patients; RRR, NNT, and CI for patients with VTE calculated from data in article using a fixed-effects model.
†Statistically significant; P value not reported.
‡Data for 138 assessable patients.
Wells PS. Review: Evidence for the effectiveness of anticoagulation therapy or prophylaxis for VTE in cancer is limited. Ann Intern Med. ;148:JC3–7. doi: 10.7326/0003-4819-148-10-200805200-02007
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Published: Ann Intern Med. 2008;148(10):JC3-7.
Hematology/Oncology, Venous Thromboembolism.
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