Risk of Arterial Thromboembolism in Patients With Cancer

Abstract

Background The risk of arterial thromboembolism in patients with cancer is incompletely understood. Objectives The authors aimed to better define this epidemiological relationship, including the effects of cancer stage. Methods Using the Surveillance Epidemiology and End Results-Medicare linked database, we identified patients with a new primary diagnosis of breast, lung, prostate, colorectal, bladder, pancreatic, or gastric cancer or non-Hodgkin lymphoma from 2002 through 2011. They were individually matched by demographics and comorbidities to a Medicare enrollee without cancer, and each pair was followed through 2012. Validated diagnosis codes were used to identify arterial thromboembolism, defined as myocardial infarction or ischemic stroke. Cumulative incidence rates were calculated using competing risk survival statistics. Cox hazards analysis was used to compare rates between groups at discrete time points. Results We identified 279,719 pairs of patients with cancer and matched controls. The 6-month cumulative incidence of arterial thromboembolism was 4.7% (95% confidence interval [CI]: 4.6% to 4.8%) in patients with cancer compared to 2.2% (95% CI: 2.1% to 2.2%) in controls (HR: 2.2; 95% CI: 2.1 to 2.3). The 6-month cumulative incidence of myocardial infarction was 2.0% (95% CI: 1.9% to 2.0%) in patients with cancer compared with 0.7% (95% CI: 0.6% to 0.7%) in controls (HR: 2.9; 95% CI: 2.8 to 3.1). The 6-month cumulative incidence of ischemic stroke was 3.0% (95% CI: 2.9% to 3.1%) in patients with cancer compared to 1.6% (95% CI: 1.6% to 1.7%) in controls (HR: 1.9; 95% CI: 1.8 to 2.0). Excess risk varied by cancer type (greatest for lung), correlated with cancer stage, and generally had resolved by 1 year. Conclusions Patients with incident cancer face a substantially increased short-term risk of arterial thromboembolism.