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WEDNESDAY, July 9, 2003 (HealthDayNews) -- The potentially fatal blood clots that plague many cancer patients are better treated with an injectable heparin drug than with an oral blood-thinning agent, a major international study finds.
This is a straightforward medical finding, yet the potential difficulty of putting it into clinical practice illustrates how financial considerations can influence medical decisions, says a physician who took part in the study.
In the study, only 27 of the 336 patients who used self-injected dalteparin, a sophisticated low-weight heparin, had recurrences after their first clot, compared to 53 of the 336 patients who were given coumarin, a standard oral drug, says a report in the July 10 issue of the New England Journal of Medicine.
Other studies have shown similar results, says Dr. Steven R. Deitcher, head of the section of hematology and coagulation medicine at the Cleveland Clinic. He has done one of those studies, which used another low-weight heparin, enoxaparin.
While Deitcher cannot give detailed results of his study because it has not yet been published in a medical journal, he says those findings are in general agreement with those of the newly published study.
Yet doctors continue to use coumarin, in large part for monetary reasons, he says. Dose for dose, a low-weight heparin costs at least 10 times more than coumarin, and Medicare does not pay for it.
It's an important issue, Deitcher says: "Cancer patients are in a very high-risk group with regards to development of blood clots, because of the underlying disease as well as many treatments."
To give just one example, the catheters that are implanted to administer drugs increase the risk of clots. "Some feel that thrombosis [clotting] is one of the most proximate causes of death in cases of solid tumors," Deitcher says.
Coumarin is a notoriously difficult drug to manage. Blood levels must be kept in a narrow range, yet they can swing erratically, especially in cancer patients. Those patients must have frequent blood tests, and they often must be hospitalized.
Avoiding those problems makes low-weight heparin "comparable in terms of cost- effectiveness," says study author Dr. Mark N. Levine, professor of medicine and clinical epidemiology and biostatistics at McMaster University in Canada.
"When you consider not only the cost of the drug but also the cost of downstream events avoided, it's a wash," he says.
Levine says he believes doctors treating cancer patients for blood clots will "undoubtedly" switch to low-weight heparin, now that they can cite the results of this study. The switch will not come quickly, but it is under way, he says.
"People now have to go through the appropriate regulatory approvals, but the first step is to prove the science," Levine says.