Risk factors for venous thromboembolic events in cancer patients

Background: Cancer patients of the Department of Internal Medicine (Cancer Research) of the Essen University Medical School (Tumor Clinics), Germany, were examined and questioned with the aim of identifying those who run a high risk of deep vein thrombosis (DVT). Patients and methods: Between September 2002 and April 2003, cancer therapy and DVT risk factors of 507 cancer patients (53% males, 47% females, mean age 56 +/- 12 years) were documented. During a mean follow-up of 8 +/- 5 months, 60 patients (12%) suffered from new venous thromboembolic events (VTE): 28 at the lower limb, 25 at the upper limb and 13 pulmonary embolisms. Results: The following factors were considered as predictive for an increased VTE risk: inpatient treatment (P < 0.0001), prior DVT in medical history (P = 0.0275), DVT in family (P = 0.0598), chemotherapy (P = 0.0080), fever (P = 0.0093) and CRP (P < 0.001). After combining factors in one variable (number of factors) the predicted VTE risk increased with the number of factors in both outpatients (OR 1.85, 95% CI 1.18-2.88, P = 0.0071) and inpatients (OR 2.34, 95% CI 1.63-3.36, P <= 0.0001). In the absence of all these factors the predicted VTE risk was 2.3%, increasing to 72% if all were present. Conclusions: In cancer patients the risk of VTE steadily increases with the number of risk factors, and identification of patients at high risk is possible.