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NEJM editorial examines use
of heparin in cancer treatment

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  • UB faculty member Elie Akl co-authored a New England Journal of Medicine editorial examining the use of the blood thinner heparin in cancer treatment. Photo: DOUGLAS LEVERE

By VERONICA MCGUIRE
Published: February 16, 2012

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 Feb. 15 in the New England Journal of Medicine, researchers from UB and McMaster University suggest that conclusive answers to key questions on the benefits of low molecular weight heparin for cancer patients remain elusive—despite promising results from large studies.

The editorial was co-authored by Elie Akl, associate professor of medicine and family medicine, School of Medicine and Biomedical Sciences, and of social and preventive medicine, School of Public Health and Health Professions, and Holger Schünemann, professor of medicine and chair of the Department of Clinical Epidemiology and Biostatistics, McMaster University. Akl also holds an appointment in McMaster’s Department of Clinical Epidemiology and Biostatistics.

In their editorial addressing a study 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, Akl and Schünemann were invited to comment on the SAVE-ONCO study of 3,200 patients with metastatic or locally advanced solid tumors. Patients receiving chemotherapy also were given a preventive dose of semuloparin (ultra-low molecular weight heparin) once daily for just over three months.

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, as well as another study Akl and Schünemann recently identified, these findings confirm and further establish the authors’ conclusion of “a likely small survival benefit.”

Akl and Schünemann estimated that “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.”

They said the findings have meaning for both patients and other health care decision makers.

“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 said.

They added that patients still will need to deal with “some uncertainty” about whether their type and stage of cancer are associated with the likely survival benefit of LMWH.

Akl and Schünemann said more clarity is required about which cancer patients would benefit most, the magnitude of this survival benefit and whether this benefit is appropriate for cancers that respond poorly to other therapies. They are planning a sophisticated analysis of the published trials—individual patient data meta-analysis—to investigate these questions.

Akl and Schünemann gratefully acknowledged Sameer K. Gunukula, an internal medicine resident at UB, for assisting in the collection of data they used to write their editorial.