Low Molecular Weight Heparin Use in Cancer Treatment

For decades, the blood thinner heparin has been used to prevent and treat blood clots. Could it be just as effective in treating cancer?

In an editorial published today in the New England Journal of Medicine, researchers from McMaster University and the University at Buffalo suggest conclusive answers to key questions on the benefits of low molecular weight heparin (LMWH) for cancer patients remain elusive - despite promising results from large studies.

Co-authors of the editorial are Dr. Elie Akl, associate professor in the Department of Medicine in UB's School of Medicine and Biomedical Sciences and in McMaster University's Department of Clinical Epidemiology and Biostatistics, and Dr. Holger Schu"nemann, professor of medicine and chair of the Department of Clinical Epidemiology and Biostatistics, McMaster University.

In their editorial, on a paper in the same issue of the journal, the physicians say the anti-clotting effect of heparin is well established, unlike a speculated anti-tumor effect. Consequently, they question if heparin should be offered to cancer patients who don't have clotting problems.

Having systematically summarized the available evidence of how cancer patients may benefit from heparin in a 2011 Cochrane Review, they now were invited to comment on the SAVE-ONCO study of 3,200 patients with metastatic or locally advanced solid tumors. Patients receiving chemotherapy were also given a preventive dose of semuloparin (ultra-low-molecular weight heparin) once daily for just over three months.

The blood thinning effect of heparin is well established, but should it be used in cancer treatment?

This study, the largest so far, found semuloparin significantly reduced the incidence of thromboembolism but had no statistically significant effect on major bleeding and death. Taken together with the prior studies and another study they recently identified these findings confirm and further establish the authors' recent review's conclusion of "a likely small survival benefit."

They estimated "if 1,000 patients with cancer were to use a prophylactic 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."

Although the blood thinner heparin has been used for several decades to prevent and treat blood clots, researchers are now questioning whether the drug could be effective in treating cancer.

Even though results from large studies have been promising, a study by investigators from McMaster University and the University at Buffalo, suggests that these studies still fail to provide precise answers to key questions, with regard to the benefits of low molecular weight heparin (LMWH) for cancer patients. The study is published today in the New England Journal of Medicine.