The incidence of venous thromboembolism among patients with primary lung cancer

Background: The incidence of venous thromboembolism (VTE) by lung cancer histology and stage is unknown. Objectives: To determine the incidence of VTE and the risk factors associated with development of VTE in a large population-based study of patients with non-small cell and small cell lung cancer. Methods: The California Cancer Registry was merged with the Patient Discharge Data Set to determine the incidence of VTE among lung cancer cases diagnosed between 1993 and 1999. Results: Among 91933 patients with newly diagnosed lung cancer, the 1-year and 2-year cumulative VTE incidences were 3.0% and 3.4%, respectively, with a person-time rate of 7.2 events/100 patient-years during the first 6months. The 1-year incidence of VTE was significantly increased in comparison to the general population [standardized incidence ratio = 21.2, 95% confidence interval (CI) = 20.4-22.0]. In a multivariate model, significant predictors of developing VTE within 1 year of non-small cell lung cancer (NSCLC) diagnosis were: younger age, the number of chronic medical comorbidities [hazard ratio (HR) = 2.8 if 3 vs. 0, 95% CI = 2.5-3.1], advancing cancer stage (HR = 4.0 for metastatic vs. local disease, 95% CI = 3.4-4.6) and adenocarcinoma histology (HR = 1.9 vs. squamous cell, 95% CI = 1.7-2.1). In multivariate models, VTE was a significant predictor of death within 2 years for both NSCLC and small cell lung cancer (SCLC), HR = 2.3, 95% CI = 2.2-2.4, and HR = 1.5, 95% CI = 1.3-1.7, respectively. Conclusions: Approximately 3% of lung cancer patients developed VTE within 2 years. The diagnosis of VTE was associated with a higher risk of death within 2 years for NSCLC and SCLC.