Predictors of active cancer thromboembolic outcomes: validation of the Khorana score among patients with lung cancer.

Objectives: Lung cancer is strongly associated with venous thromboembolism (VTE), but primary prevention against VTE is not a validated management strategy. Risk assessment models will be necessary for efficient implementation of preventative strategies. Materials and methods: Utilizing a prospectively collected lung cancer database, we aimed to validate the Khorana Risk Score (KRS) in the prediction of VTE among patients with lung cancer. VTE events were retrospectively identified by reviewers unaware of the clinical prediction score calculation. The association between KRS and the risk of VTE was examined using cumulative incidence function with competing risk models. Mortality prediction was evaluated as a secondary outcome. Results: We included 719 patients in our review. The patients were predominantly older men with non-small cell lung cancer and 40% had metastatic disease at inception. The median follow-up was 15.2 months. There were 83 VTEs (11.5%) and 568 (78.8%) patients died. A high KRS (cumulative incidence, 12.4%; 95% confidence interval [CI], 6.4-20.5%) was not associated with VTE compared with an intermediate score (cumulative incidence, 12.1%; 95% confidence interval, 9.5-15.0%) in both univariate and multivariable analyses. However, a high KRS was a predictor of mortality (hazard ratio, 1.7; 95% CI, 1.4-2.2). Conclusions: Among patients with lung cancer, the KRS did not stratify the patients at the highest risk of VTE. Improved risk stratification methods are needed for this group of patients prior to implementing a primary prevention strategy.