Variation in Venous Thromboembolism Outcomes Based on Primary Cancer Site A RIETE Registry Analysis

Abstract

BACKGROUND: Patients with cancer-associated venous thromboembolism (VTE) are at increased risk of both recurrent VTE and bleeding. These risks may vary by cancer site, but the magnitude of this variation remains unclear. OBJECTIVES: The aim of the study was to compare 90-day risks of recurrent VTE or VTE-related death (composite outcome) and major bleeding across different cancer sites. METHODS: We analyzed 18,660 patients with active cancer and VTE and 88,162 without cancer in the RIETE (Registro Informatizado de la Enfermedad Tromboembólica) registry. Multivariable Cox models and Fine-Gray competing risk analyses were used. Sensitivity analyses included propensity score matching and subgroup stratification by cancer site. RESULTS: Within 90 days, 4.0% of cancer-associated thrombosis patients experienced the composite outcome (fatal pulmonary embolism: 1.4%; VTE recurrence: 3.0%), and 3.4% had major bleeding. Compared to noncancer patients, cancer-associated thrombosis patients had higher risks of the composite outcome (adjusted HR [aHR]: 2.54; 95% CI: 2.21 to 2.93) and major bleeding (aHR: 1.40; 95% CI: 1.22-1.61). The highest thrombotic risk was found in lung (aHR: 4.03; 95% CI: 3.38-4.81) and pancreatic cancers (aHR: 3.85; 95% CI: 3.04-4.88), followed by gastrointestinal (aHR: 1.95; 95% CI: 1.53-2.48) and breast (aHR: 1.63; 95% CI: 1.27-2.09) cancers. Major bleeding risk was highest in gastrointestinal (aHR: 1.66; 95% CI: 1.37-2.00), genitourinary (aHR: 1.66; 95% CI: 1.38-2.00), and pancreatic cancers (aHR: 1.43; 95% CI: 1.05-1.95). Results were consistent in the propensity-matched cohort. CONCLUSIONS: VTE and bleeding risks in cancer-associated thrombosis vary substantially by cancer site. These findings support a personalized approach to anticoagulation in cancer patients with VTE.