Cancer Patients Have Increased Risk for Blood Clots
Reported February 9, 2005
(Ivanhoe Newswire) — A new study shows cancer patients have a seven-fold increased risk for venous thrombosis, or blood clots in the legs or lungs.
Researchers at the Leiden University Medical Center in Leiden, the Netherlands, say the risk of venous thrombosis has been shown to be increased in patients with cancer, however it is unclear of the risk based on various cancer types and stages.
Researchers studied 3,220 patients, ages 18 to 70, who had a blood clot in their legs or lungs. They evaluated different tumor sites, the presence of distant metastases, and carrier status of gene mutations. Patients underwent anticoagulant (anti-clotting) therapy, and then a blood sample was taken. DNA was isolated to determine gene mutations, factor V Leiden and prothrombin 20210A, both linked to thrombosis.
Researchers found the overall risk of venous thrombosis was increased seven-fold in patients with cancer vs. persons without cancer. Patients with hematological (blood-related) malignancies had a 28-fold increased risk of venous thrombosis, followed by those with lung cancer and gastrointestinal cancer. In the first few months after the diagnosis of cancer, the risk of venous thrombosis was highest (53-times greater risk). Patients with cancer with distant metastases had a higher risk compared to patients without distant matastases (20-times greater risk). Cancer patients who also carry the V Leiden mutation had a 12-fold increased risk vs. individuals without cancer and factor V Leiden. Similar results were indirectly calculated for the prothrombin 20210A mutation in patients with cancer.
For patients with cancer who have an increased risk to develop venous thrombosis, prophylactic anticoagulant therapy may be more cost effective than screening for the factors. “Screening for factor V Leiden and prothrombin 20210A mutation and subsequent prophylactic anticoagulant therapy with an effectivity of 80 percent would prevent annually seven to 27 venous thrombotic events per 10,000 patients with cancer screened, which does not make screening a useful strategy,” the authors conclude.
SOURCE: The Journal of the American Medical Association, 2005;293:715-722