Heparin is a blood thinner that's been used for years to prevent and treat blood clots. The question is, could this medication also be used to treat cancer?
Despite impressive results from large studies, two researchers are questioning the benefits of using low molecular weight heparin (LMWH) in cancer patients.
Dr. Elie Akl, associate professor of medicine at the University of Buffalo, and Dr. Holger Schünemann, professor of medicine and chair of the Department of Clinical Epidemiology and Biostatistics at McMaster University, wrote an editorial published February 15, 2012 in the New England Journal of Medicine.
They say that while the anti-clotting benefits of LMWH are well-known, its anti-tumor effects are not. Consequently, they suggest that the drug not be used in patients who do not have clotting problems.
Akl and Schünemann summarized all available evidence regarding the cancer benefits of heparin in a 2011 Cochrane Review. They were asked to comment on a subsequent study (SAVE-ONCO) of 3,200 patients with advanced or metastatic tumors.
In this study, patients who were receiving chemotherapy were also a once daily dose of semuloparin (ultra-low-molecular weight heparin) for about three months.
Findings from this research suggested that the medication significantly reduced the incidence of blood clots, but did not impact major bleeding or mortality, from a statistically significant perspective.
The authors estimated that if 1,000 patients with cancer were to use a prophylactic [preventive] dose of LMWH, approximately 30 would avert death, 20 would avert a clotting complication and one would suffer a major bleeding episode over a 12-month period.”
“Patients who are not bothered much by daily injections of LMWH can avert hospitalizations for a clotting complication and possibly achieve a prolongation of life if they accept an increased risk of bleeding and its subsequent treatment,” they wrote.
The researchers say more study and clarity are need to understand who may benefit from heparin, the exact nature of any survival benefits and what types and stages of cancer are associated with these benefits.
To learn the answers to these questions, Akl and Schünemann are planning sophisticated analysis of published trials.