Purpose: Patients with cancer are at risk of venous thromboembolism (VTE). Tumor-related factors could help estimate patients' individual risk for VTE. Currently, only scarce information on the association between tumor grade and VTE is available. We thus evaluated the role of tumor grade and its association with VTE.
Patients and methods: The Vienna Cancer and Thrombosis Study is a prospective, observational cohort study including patients with newly diagnosed cancer or progression of disease after remission. Study end point is the occurrence of symptomatic VTE.
Results: Seven hundred forty-seven patients with solid tumors received follow-up for a median of 526 days. VTE occurred in 52 patients (7.0%). At study inclusion, 468 patients had low-grade tumors (G1 and G2) and 279 had high-grade tumors (G3 and G4). In multivariable Cox regression analysis including tumor grade, tumor histology, tumor sites, stage, sex, and age, patients with high-grade tumors had a significantly higher risk of VTE compared with those with low-grade tumors (hazard ratio, 2.0; 95% CI, 1.1 to 3.5; P = .015). The cumulative probability of developing VTE after 6 months was higher in patients with high-grade tumors than in those with low-grade tumors (8.2% v 4.0%; log-rank test P = .037). Patients with high-grade tumors had higher D-dimer levels (P = .008) and leukocyte counts (P < .001), and lower hemoglobin levels (P = .008).
Conclusion: The tumor grade may help identify patients with cancer who are at high risk of VTE. The association of tumor grade with recently identified biomarkers indicates a link between tumor differentiation and pathogenesis of cancer-associated VTE.