Most Cancer-related Blood Clots Occur in Outpatients
In a study of nearly 18,000 people with cancer, University of Rochester Medical Center researchers have found that when blood clots develop – a well-known and serious complication of cancer treatment – 78 percent of the time they occur when a person is out of the hospital, at home or elsewhere, while on chemotherapy.
This data is striking because, until now, outpatients have not been systematically studied, and previous data gathered on the incidence of blood clots was mostly from those hospitalized, who tend to be sicker. However, with a shift toward outpatient cancer treatment, future efforts to prevent blood clots should focus on helping people to avoid complications so they can continue to live fully, by working, raising children, and exercising, during cancer care, says Alok Khorana, MD, associate professor in the James P. Wilmot Cancer Center at URMC.
Clots form most often in the legs, lungs, or abdomen and are life-threatening if not treated.
“One in five patients develops blood clots after a cancer diagnosis, and we believe that number is rising,” Dr. Khorana says. “The Surgeon General recently issued a Call to Action to reduce venous thromboembolism. At this point, public health efforts have focused on inpatient prophylaxis. These new data suggest that to reduce the burden of VTE in cancer patients, prevention efforts will have to shift to the outpatient arena as well.”
The medical term venous thromboembolism is a mass of red blood cells, clotting proteins, and platelets that block the normal flow of blood. Clots form most often in the legs, lungs, or abdomen and are life-threatening if not treated.
People with cancer are more prone to blood clots for many reasons: the malignancy itself can secrete proteins associated with blood clots; several treatments (including surgery, chemotherapy, and hormonal therapy) raise the clot risk; decreased mobility due to active disease or hospitalization; a genetic predisposition; or having other health problems, such as infections, obesity, anemia, and lung disorders. And once a blood clot occurs, a person with cancer is much more likely to have other clots later.
“Ongoing public health issues that we must address are how to educate patients on the importance of blood clot prevention and improving compliance to preventive treatment,” Dr. Khorana says. People with cancer should immediately report to their physicians any unusual symptoms, such as swelling or redness in limbs or shortness of breath, even if they are otherwise feeling well.
The Rochester group published a risk model in the journal Blood, and based partly on research from the group, the American Society of Clinical Oncology, in 2007, issued its first set of guidelines for clinicians for the prevention of blood clots in people with cancer.
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This article was originally published in Coping® with Cancer magazine, January/February 2012.