Comparison of risk prediction scores for venous thromboembolism in cancer patients: a prospective cohort study.

In ambulatory patients with solid cancer, routine thromboprophylaxis to prevent venous thromboembolism is not recommended. Several risk prediction scores to identify cancer patients at high risk of venous thromboembolism have been proposed, but their clinical usefulness remains a matter of debate. We evaluated and directly compared the performance of the Khorana, Vienna, PROTECHT, and CONKO scores in a multinational, prospective cohort study. Patients with advanced cancer were eligible if they were due to undergo chemotherapy or had started chemotherapy in the previous three months. The primary outcome was objectively confirmed symptomatic or incidental deep vein thrombosis or pulmonary embolism during a 6-month follow-up period. A total of 876 patients were enrolled, of whom 260 (30%) had not yet received chemotherapy. Fifty-three patients (6.1%) developed venous thromboembolism. The c-statistics of the scores ranged from 0.50 to 0.57. At the conventional positivity threshold of 3 points, the scores classified 13-34% of patients as high-risk; the 6-month incidence of venous thromboembolism in these patients ranged from 6.5% (95%CI: 2.8-12) for the Khorana score to 9.6% (95%CI: 6.6-13) for the PROTECHT score. High-risk patients had a significantly increased risk of venous thromboembolism when using the Vienna (subhazard ratio 1.7; 95%CI: 1.0-3.1) or PROTECHT (subhazard ratio 2.1; 95%CI: 1.2-3.6) scores. In conclusion, the prediction scores performed poorly in predicting venous thromboembolism in cancer patients. The Vienna CATS and PROTECHT scores appear to discriminate better between low- and high-risk patients, but further improvements are needed before they can be considered for introduction into clinical practice.

Prevention and Treatment of Venous Thromboembolism in Patients with Cancer: Focus on Drug Therapy.

Venous thromboembolism (VTE) is a frequent complication in patients with cancer and is associated with significant morbidity and mortality. The use of anticoagulants for the prevention and treatment of VTE in this population is challenging given the high risk of both recurrent VTE and bleeding complications. Thromboprophylaxis with subcutaneous low-molecular-weight heparin (LMWH) is recommended in cancer patients hospitalized for an acute medical illness and in those undergoing major surgery. In ambulatory cancer patients with or without central venous catheters, routine thromboprophylaxis is not recommended because of the relatively low benefit-to-risk ratio. To identify cancer outpatients at very high risk of VTE who may benefit from thromboprophylaxis, VTE risk stratification tools based on tumour type, clinical parameters, or coagulation biomarkers have been proposed, but their clinical utility needs validation. The mainstay of treatment for cancer-associated VTE is LMWH for at least 6 months or longer in case of active disease. The same initial and long-term treatment for incidental VTE as for symptomatic VTE can be suggested while awaiting additional studies in this area.