Prophylaxis against Venous Thrombosis in ambulatory patients with Cancer

A venous thrombotic event increases the risk of death and morbidity in cancer patients, and can delay active cancer treatment. Medical prophylaxis reduces the incidence of venous thrombosis in ambulatory cancer patients and is therefore recommended to ambulatory cancer patients with high risk of venous thrombosis.

There are subtle differences in current guidelines for recommendations of thrombosis prophylaxis in ambulatory cancer patients, but all advice against the use of routine prophylaxis against venous thrombosis in most cancer patients.  An exception is made for patients with multiple myeloma who require treatment with the medicines thalidomide or lenalidomide with high doses of steroids.

Cancer is associated with a 4-7 fold higher risk of venous thrombosis than people without cancer. The risk of cancer varies between cancer types and increases with active treatment (surgery, chemotherapy and radiation), inherited risk of venous thrombosis, and disseminated (metastatic) disease.  Venous thrombosis is the second cause of death in cancer patients after the cancer itself.  The number of cancer patients with venous thrombosis is increasing due to prolonged survival, increase in prothrombotic treatment modalities, aging population and improved diagnostic tools.  

In 2008 Professor Har Gobid Khorana at the Massachusetts Institute of Techology  published a scoring system to assess risk of venous thrombosis in ambulatory patients with cancer.  In the model, cancer type (0-2 points), high platelet count (0-1 point), low hemoglobin concentration (0-1 point), high leukocyte count (0-1 point), and obesity (0-1 point) were assessed before start of chemotherapy.  Thrombosis prophylaxis is recommended with a total score of 3 or above. Other risk factor of venous thrombosis such as prolonged immobilization, treatment with hormones or anti-angiogenic drugs, previous history of venous thrombosis, compression of blood vessels, and inherited risk factors should be considered when decisions should be made regarding thrombosis prophylaxis in ambulatory cancer patients.

There has been published two large clinical studies that have evaluated the impact of antithrombotic treatment to prevent venous thrombosis in ambulatory cancer patients.  A significant decrease in the incidence of VTE-events occurred in cancer-patients receiving prophylaxis.  The effect of prophylaxis on morbidity and mortality has never been properly investigated.

The risk of bleeding complications is similar for different cancers, except for leukemias where increased risk of bleeding is noticed due to low platelet counts either caused by the disease itself or as a consequence of treatment.  Previous studies have not shown a consistent increased risk of serious bleeding complications by prophylactic antithrombotic treatment.  Bleeding complications secondary to prophylactic doses (low) are also less complicated to handle than bleeding complications secondary to therapeutic (high) doses of antithrombotic treatment. 

The article is published in New England Journal of Medicine

Reference: Jean M, Connors JM. Prophylaxis against venous thromboembolism in ambulatory patients with cancer. DOI:  10.1056/NEJMra1401468



Page administrator: Helle Jørgensen
Last updated: 18.09.2014 13:57
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