No Evidence Not to Prescribe Thromboprophylaxis in Hospitalized Medical Patients with Cancer

We read with great interest the literature review by Carrier et al indicating the lack of evidence to support thromboprophylaxis in hospitalized medical patients with cancer. However, this paper will change little if any of our clinical practice. The authors acknowledge that only 3 placebo-controlled studies, including 307 cancer patients, were analyzed. Moreover, the site and the stage of the cancers were not indicated, whereas patients with cancer are at high risk for deep vein thrombosis and pulmonary embolism, a common cause of death, depending on both tumor site and disease stage. Of note, several current guidelines strongly recommend routine thrombophylaxis. Indeed, pathogenesis of thromboembolic complications involves venous stasis due to immobilization and venous compression, endothelial damage related to chemotherapy and venous catheters, and blood hypercoagulability such as thrombocytosis and hyperfibrinogenemia. Risk factors for venous thromboembolism in cancer patients are well known, including patient-related factors (age >65 years, comorbid conditions, prior history of venous thromboembolism, heritable thrombophilia), cancer-related factors (pancreatic, gastrointestinal, lung primary site; initial 3-6 months after diagnosis; current metastatic disease), and treatment-related factors (such as current hospitalization, active chemotherapy, active hormonal therapy, and thalidomide or lenalidomide therapy). Thromboprophylaxis is recommended, at least in these patients with acute illness at high risk for thromboembolic events. Conversely, thromboprophylactic treatment is clearly underutilized in nonsurgical cancer patients with acute medical illness cancer (<40% of patients).

In conclusion, we will continue to prescribe thromboprophylactic treatment in our hospitalized medical patients with cancer at high risk when there are no contraindications to such therapy, and we encourage our colleagues to improve compliance to current guidelines.