Blood Journal
Leading the way in experimental and clinical research in hematology

Development and validation of a predictive model for chemotherapy-associated thrombosis

  1. Alok A. Khorana1,
  2. Nicole M. Kuderer2,
  3. Eva Culakova2,
  4. Gary H. Lyman2, and
  5. Charles W. Francis1
  1. 1James P. Wilmot Cancer Center and the Department of Medicine, University of Rochester, NY; and
  2. 2Duke University Medical Center and the Duke Comprehensive Cancer Center, Durham, NC

Abstract

Risk of venous thromboembolism (VTE) is elevated in cancer, but individual risk factors cannot identify a sufficiently high-risk group of outpatients for thromboprophylaxis. We developed a simple model for predicting chemotherapy-associated VTE using baseline clinical and laboratory variables. The association of VTE with multiple variables was characterized in a derivation cohort of 2701 cancer outpatients from a prospective observational study. A risk model was derived and validated in an independent cohort of 1365 patients from the same study. Five predictive variables were identified in a multivariate model: site of cancer (2 points for very high-risk site, 1 point for high-risk site), platelet count of 350 × 109/L or more, hemoglobin less than 100 g/L (10 g/dL) and/or use of erythropoiesis-stimulating agents, leukocyte count more than 11 × 109/L, and body mass index of 35 kg/m2 or more (1 point each). Rates of VTE in the derivation and validation cohorts, respectively, were 0.8% and 0.3% in low-risk (score = 0), 1.8% and 2% in intermediate-risk (score = 1-2), and 7.1% and 6.7% in high-risk (score ≥ 3) category over a median of 2.5 months (C-statistic = 0.7 for both cohorts). This model can identify patients with a nearly 7% short-term risk of symptomatic VTE and may be used to select cancer outpatients for studies of thromboprophylaxis.

  • Submitted October 5, 2007.
  • Accepted January 19, 2008.
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