The 12-month cumulative incidence of VTE is currently 3% following cancer diagnosis, which is 9-fold higher than in the general population.
Over the past two decades, VTE risk in cancer patients increased 3-fold overall and 6-fold in those using chemotherapy or targeted therapy.
The incidence of venous thromboembolism in cancer patients may have changed in the past decade, possibly due to novel cancer therapies, improved survival, and high-resolution imaging. Danish medical registries were used to identify 499,092 patients with a first-time cancer diagnosis between 1997 and 2017, who were matched to 1,497,276 comparison individuals without cancer from the general population. We computed cumulative incidences of venous thromboembolism 6 and 12 months after the diagnosis/index date. Hazard ratios (HRs) were calculated using Cox regression. Risk factors were examined by computing subdistribution hazard ratios (SHRs) in a competing risk analysis. Cumulative incidence of venous thromboembolism 12 months after the cancer diagnosis/index date was 2.3% (95% confidence interval (CI), 2.2%-2.3%) in the cancer cohort and 0.35% (95% CI, 0.34%-0.36%) in the comparison cohort (HR, 8.5; 95% CI, 8.2-8.8). Important risk factors for cancer patients were prior venous thromboembolism (SHR, 7.6; 95% CI, 7.2-8.0), distant metastasis (SHR, 3.2; 95% CI, 2.9-3.4), and use of chemotherapy (SHR, 3.4; 95% CI, 3.1-3.7), protein kinase inhibitors (SHR, 4.1; 95% CI 3.4-4.9), anti-angiogenic therapy (SHR, 4.4; 95% CI, 3.8-5.2), and immunotherapy (SHR, 3.6; 2.8-4.6). Twelve-month incidence in the cancer cohort increased from 1.0% (95% CI, 0.9%-1.2%) in 1997 to 3.4% (95% CI, 2.9%-4.0%) in 2017, which was paralleled by improved 12-month survival and increased use of computed tomography (CT) scans, chemotherapy, and targeted therapies. In conclusion, the risk of venous thromboembolism in cancer patients is increasing steadily and is 9-fold higher than in the general population.