Incidence and risk factors of venous thromboembolic events in lymphoma

Cancer patients are at increased risk of venous thromboembolism; however, the incidence and risk factors for venous thromboembolism in lymphoma patients are not well defined.

Medical records of 422 newly referred lymphoma patients at our institution were reviewed over 2-year follow-up for all venous thromboembolism events and potential risk factors. Multivariate logistic regression model was used to identify risk factors predictive of venous thromboembolism.

Among 422 patients, 72 (17.1 %) had 80 new episodes of venous thromboembolism: 59 had deep vein thrombosis, 17 had pulmonary embolism, and 4 had combined deep vein thrombosis and pulmonary embolism. Only 18 of 422 patients (4.3%) were on thromboprophylaxis at baseline. Interestingly, 64% (51/80) of the episodes occurred by the third cycle of chemotherapy. By multivariate logistic regression, female sex (odds ratio [OR] 3.51, P=.001), high hemoglobin (OR 1.26, P=.020), high serum creatinine (OR 3.23, P=.009), and doxorubicin- or methotrexate-based chemotherapy (OR 3.47, P=0.003) were important risk factors for new venous thromboembolism.

Lymphoma patients are at high risk for venous thromboembolism in the initial cycles of chemotherapy; the risk was higher for women, patients with elevated hemoglobin or creatinine, or those receiving doxorubicin or methotrexate. Future studies might focus on validation of these risk factors to identify the high-risk cohort and the potential role of thromboprophylaxis, particularly during initial cycles of chemotherapy.