Among patients with cancer, the risk for venous thromboembolism (VTE) is much greater than that in the general population, and has been increasing over the past 2 decades, according to a population-based cohort study published in Blood.

VTE represents a significant and established risk among patients with cancer, though there is a lack of recent VTE incidence estimations among patients with cancers, and previous studies may have overestimated this risk. For this study, researchers evaluated data from Danish medical registries to determine VTE risk among patients with cancer, and to describe if and how this risk has changed.

The researchers identified and included data from 499,092 patients with cancer diagnosed between 1997 and 2017; a comparison cohort of 1,497,276 individuals from the general population were also included. At baseline, in the cohort of patients with cancer, the mean age was 68 years, 253,745 (50.8%) were women, the majority (294,392; 59.0%) underwent surgery, and 386,018 (77.3%) had a Charlson Comorbidity Index score of 0. In the general population cohort, the median age was 68 years, 761,235 (50.8%) were women, and 1,198,086 (80%) had a Charlson Comorbidity Index score of 0.

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Overall, 12 months after cancer diagnosis or date of indexing, 2.3% of patients had a VTE, compared with 0.35% in the general population (hazard ratio [HR], 8.5; 95% CI, 8.2-8.8). Prior VTE (sub-distribution [S] HR, 7.6; 95% CI, 7.2-8.0), distant metastasis (SHR, 3.2; 95% CI, 2.9-3.4), chemotherapy use (SHR, 3.4; 95% CI, 3.1-3.7), protein kinase inhibitor use (SHR, 4.1; 95% CI, 3.4-4.9), anti-angiogenic therapy use (SHR, 4.4; 95% CI, 3.8-5.2), and immunotherapy use (SHR, 3.6; 95% CI, 3.8-5.2) were each linked with a greater VTE risk.

While the 12-month VTE risk in the population of patients with cancer was 1% in 1997, patients with cancers diagnosed in 2017 faced a 12-month VTE risk of 3.4%. Improved survival and the increased use of computed tomography and chemotherapies/novel therapies may, according to the authors, help to explain this increased risk.

“This study demonstrated that risk of VTE is currently 12-fold higher in cancer patients than in the general population, taking death into account as a competing risk,” the authors wrote. “For cancer patients receiving chemotherapy or targeted therapy, this risk is currently 23-fold increased.”

Disclosures: Some authors have declared affiliations with or received funding from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


Mulder FI, Horvàth-Puhó E, van Es N, et al. Venous thromboembolism in cancer patients: a population-based cohort study. Blood. Published online November 10, 2020. doi:10.1182/blood.2020007338