Arterial Thromboembolism in Cancer Patients: A Danish Population-Based Cohort Study

Background: The relation between cancer and arterial thromboembolism (ATE) remains unclear.

Objectives: The purpose of this study was to evaluate ATE risk in cancer patients.

Methods: Danish registries were used to identify all cancer patients between 1997 and 2017, each matched to three cancer-free comparator individuals. ATE was defined as the composite of myocardial infarction, ischemic/unspecified stroke, and peripheral arterial occlusion. A competing risk approach was used to compute cumulative incidences and subdistribution hazard ratios (SHRs). Cause-specific hazard ratios (HRs) were calculated using Cox regression. Among cancer patients, mortality risk was estimated in Cox regression analysis by treating ATE as a time-varying exposure. Patients were followed for 12 months.

Results: The study included 458,462 cancer patients and 1,375,386 comparator individuals. In the 6-month period following cancer diagnosis/index date, the cumulative incidence for ATE was 1.50% (95% confidence interval [CI]: 1.47% to 1.54%) in cancer patients and 0.76% (95% CI: 0.75% to 0.77%) in comparator individuals (HR: 2.36; 95% CI: 2.28 to 2.44). Among cancer patients age <65 years, 65 to 75 years, and >75 years, this was 0.79% (95% CI: 0.74% to 0.83%), 1.61% (95% CI: 1.55% to 1.67%), and 2.30% (95% CI: 2.22% to 2.38%), respectively. Other predictors for ATE among cancer patients were prior ATE (SHR: 2.96; 95% CI: 2.77 to 3.17), distant metastasis (adjusted SHR: 1.21; 95% CI: 1.12 to 1.30), and chemotherapy (SHR: 1.47; 95% CI: 1.33 to 1.61). Among cancer patients, ATE was associated with an increased risk of mortality (HR: 3.28; 95% CI: 3.18 to 3.38).

Conclusions: Cancer patients are at increased risk of ATE. Clinicians should be aware of this risk, which is associated with mortality.