Anticoagulation for the initial treatment of venous thromboembolism in patients with cancer: a systematic review.
BACKGROUND
The authors compared the relative efficacy and safety of low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) for the initial treatment of venous thromboembolism (VTE) between patients with and without cancer.


METHODS
By using Cochrane methodology for systematic reviews, separate meta-analyses were conducted for subgroups of patients with and without cancer, and relative risks (RRs) were compared for statistical significance. The methodologic quality for each outcome was assessed by using the Grading of Recommendations Assessment, Development, and Evaluation approach.


RESULTS
LMWH reduced mortality significantly compared with UFH in patients with cancer (RR of 0.71; 95% confidence interval [95% CI], 0.52-0.98 [moderate-quality evidence]) but not in patients without cancer (RR of 0.97; 95% CI, 0.65-1.46 [low-quality evidence]). However, the difference in the RR for the 2 subgroups did not reach statistical significance (P = .113). The difference between LMWH and UFH in the effect on recurrent VTE was not statistically significant in the subgroup with cancer (RR of 0.78; 95% CI, 0.29-2.08 [low-quality evidence]), in the subgroup without cancer (RR of 0.94; 95% CI, 0.60-1.46 [low-quality evidence]), or between the 2 subgroups (P = .367). No data were available for bleeding outcomes, thrombocytopenia, or postphlebitic syndrome.


CONCLUSIONS
The current results indicated that LMWH most likely is superior to UFH in reducing mortality in the initial treatment of VTE for patients with cancer. There is a need for more and better designed trials to confirm these findings.
Akl
Elie A
EA
Department of Medicine, State University of New York at Buffalo, Buffalo, New York 14215, USA. elieakl@buffalo.edu
Rohilla
Sandeep
S
Barba
Maddalena
M
Sperati
Francesca
F
Terrenato
Irene
I
Muti
Paola
P
Bdair
Fadi
F
Schünemann
Holger J
HJ
D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D006493:Heparin / Q000009:adverse effects / Q000627:therapeutic use*; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D009369:Neoplasms / Q000150:complications*; D054556:Venous Thromboembolism / Q000188:drug therapy*
D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight; D006493:Heparin