Venous Thromboembolic Events in Cancer Immunotherapy: A Narrative Review

Venous thromboembolism (VTE) represents a significant complication of cancer immunotherapy, with emerging evidence suggesting distinct pathophysiological mechanisms compared to traditional chemotherapy-associated thrombosis. This narrative review examines the epidemiology and pathogenesis of VTE in patients receiving immunotherapies for cancer including immune checkpoint inhibitors (ICIs), chimeric antigen receptor (CAR) T-cell therapy, bispecific T-cell engagers (BiTEs), among others. Real-world studies demonstrate a wide range of VTE incidence rates in ICI recipients, with potential mechanisms including exacerbated underlying interleukin-8-mediated inflammatory pathways and consequent neutrophil extracellular trap (NET) formation. CAR T-cell therapy is associated with unique hemostatic challenges, including concurrent thrombotic and bleeding risks related to cytokine release syndrome. Current risk assessment tools show limited predictive utility in patients receiving immunotherapies for cancer, highlighting the need for novel stratification models. Future research priorities include developing immunotherapy-specific risk prediction tools, elucidating mechanistic pathways linking immune activation to thrombosis, and establishing evidence-based and tailored thromboprophylaxis strategies. As cancer immunotherapy continues to evolve, understanding and mitigating thrombotic complications remains crucial for optimizing patient outcomes.