Targeting patients for anticoagulant prophylaxis trials in patients with cancer: Who is at highest risk?

Introduction: It is not clear which cancer patients are at highest risk for developing venous thromboembolism (VTE). Materials and Methods: The epidemiology of VTE in cancer patients was investigated by linking the California Cancer Registry database to the discharge records of all patients hospitalized in California public hospitals between 1993-1999. Nineteen types of cancer were studied, four in detail. Results and Conclusions: The incidence of VTE was highest in patients who presented with metastatic cancer, particularly clinically aggressive cancers associate with a high one-year mortality rate, such as pancreatic cancer. The incidence of VTE increased as the number of chronic medical co-morbid conditions increased. The incidence of VTE was highest in the first few months after diagnosis, and decreased over time, even when the death rate due to cancer remained constant. Patients with glioma had a very high incidence of VTE after invasive neurosurgery, whereas patients with solid cancers who underwent major surgery had a tower risk of developing VTE compared to patients who did not undergo major surgery. Development of VTE was associated with significantly shortened survival compared to cancer patients without VTE matched for age, race, sex, initial cancer stage and time after cancer diagnosis. This effect of VTE on survival was greatest in patients initially diagnosed with local or regional stage solid cancer as VTE was associated with emergence of metastatic disease. If primary thromboprophylaxis of cancer patients is considered, treatment should begin immediately after cancer diagnosis, and it should be targeted toward patients who have a biologically aggressive cancer that is initially metastatic and/or toward patients who have several chronic co-morbid conditions. Secondary thromboprophylaxis should be targeted toward patients who have evidence of an ongoing active malignancy. Glioma patients are at very high risk in the 3 month period immediately after invasive neurosurgery. (c) 2007 Elsevier B.V. All rights reserved.