Blood Clots a Common Risk for Some Cancer Patients

Venous thromboembolisms seen up to a year after some cancer treatments

(RxWiki News) As if cancer treatment isn't rigorous enough, patients are often at risk of additional medical problems for months afterwards. New research has uncovered that some cancer patients face an increased risk of developing blood clots.

Duke University researchers have found that blood clots are more common for some cancer patients than previously thought. In fact, 20 percent, one of every five patients, will develop a blood clot known as a venous thromboembolism (VTE) at some point during the year following cancer treatment.

"Ask your doctor what you can do to prevent blood clots."

In about two percent of cases, these clots are deadly. They form deep in the veins of the legs or pelvis and can move to the lungs where they block off blood flow.

These complications also drive up the cost of care as they require additional hospitalization for patients. Study authors estimate patients who have blood clots have an average bill of $110,362, as compared to $77,984 for those who don't have VTEs.

Lead author Gary H. Lyman, M.D., M.P.H., a professor of medicine and director of the Comparative Effectiveness and Outcomes Research Program at Duke, says costs are significantly greater for patients with VTEs and still don't include expenses for caregivers, out-of-pocket costs and "the intangible costs of pain and suffering."

For the study, Dr. Lyman and colleagues used the InVision Data Mart Multiplan/ Integrated Health Care Information Solutions (data on more than 17 million U.S. medical patients) to evaluate 30,552 cancer cases.

Investigators focused on patients with bladder, colon, lung, pancreatic, stomach, rectum and ovarian cancers who had chemotherapy between 2004 and 2008.

Risks of developing VTEs within 3.5 months of starting treatment varied widely, depending on the type of cancer, with bladder cancer carrying the lowest risk (4.8 percent) and pancreatic cancer having the highest (11.9 percent).

A year after treatment, risks of VTEs nearly doubled for patients:

  • 9.9 percent for bladder cancer
  • 21.5 percent pancreatic cancer 
  • 11.9 percent colorectal
  • 11.4 percent ovary
  • 14.8 percent lung
  • 16.7 percent stomach 

While the cause of VTEs is not fully understood, Dr. Lyman says scientists believe contributing factors may include blood clotting agents that tumors release, chemotherapy side effects and pre-existing conditions such as obesity and anemia.

This study allows physicians to know which patients are at highest risk, and could lead to better preventive use of blood thinners, Dr. Lyman says. But these medicines carry their own set of risks.

This study was presented at the 2011 European Multidisciplinary Cancer Congress in Stockholm.

Research that has not yet been published in a peer-reviewed journal is considered preliminary.

Review Date: 
November 11, 2011