Treating, Preventing Deadly Blood Clots In Cancer Patients
An international panel of researchers led by an oncologist from the Duke Comprehensive Cancer Center has put together a set of guidelines for the prevention and treatment of dangerous blood clots that threaten cancer patients.
"Cancer patients are at increased risk for what is known as venous thromboembolism -- or the formation of a blood clot -- which can be deadly," said Gary Lyman, M.D., director of the Health Services and Outcomes Research Program in Oncology at Duke and co-chair of ASCO's Venous Thromboembolism Expert Panel. "These new guidelines will give clinicians some of the tools they need to prevent and treat this dangerous complication of cancer."
The guidelines, which are based on studies that have been reported in the medical literature, will be published in the December 1, 2007 issue of the Journal of Clinical Oncology. They will also appear early online on the American Society of Clinical Oncology Web site on October 29, 2007.
It is estimated that venous thromboembolism (VTE) affects four to 20 percent of cancer patients, and is one of the leading causes of death in this population, Lyman said.
"We have long known that there is an association between cancer and risk for VTE, and we can speculate what some of the reasons for this link might be," he said. "Tumor cells may release proteins that encourage clotting, and these patients are often bedridden and immobile, which also puts them at increased risk."
Treatments, especially newer ones such as the anti-angiogenesis agents which work by cutting off a tumor's blood supply, may also increase the risk of VTE, Lyman said.
Anticoagulants, or blood thinners, are the primary treatment for blood clots, and the new guidelines suggest using them preventatively in populations that are at-risk, including hospitalized cancer patients.
"The guidelines also suggest that cancer patients who develop a blood clot should be treated with an anticoagulant for at least six months afterwards," Lyman said. "On the flip side, our guidelines recommend that patients who are not hospitalized should not be routinely treated with an anticoagulant, unless they are receiving certain types of therapies that may increase risk."
Lyman said patients should be aware of their risk and ask their doctors about how to minimize it.
"The message to patients is to add this to the list of things to ask your doctor about," he said. "What can I do to minimize my risk of blood clots? Do I need to be considered for a blood thinner, and if so, at what point in time?"