Presentation Highlights

On Monday at the 2017 ISTH Congress, Ingrid Pabinger, M.D., ISTH Council Chair, presented the results of the development and validation of a cancer-related venous thromboembolism (VTE) risk assessment model to the Oral Communication Session attendees:

  • Two cohorts of patients with solid tumors were used to develop and validate a new VTE risk assessment model.
  • This model, which included only one clinical factor (tumor site) and one biomarker (D-dimer), was found to be predictive of VTE risk, and may aid physicians in selecting appropriate candidates for thromboprophylaxis.

The risk of VTE is often underappreciated in patients with cancer. This model may further help to elucidate VTE risk in these patients.

Venous thromboembolism (VTE) occurs commonly in cancer patients. However, not every cancer patient has the same level of risk, therefore it is important to identify patients who are at high risk of VTE. Two prospective cohorts of patients with solid tumors, the Vienna Cancer and Thrombosis Study (CATS, n=1,423), and the Multinational cohort study to Identify CAncer patients at high risk of VTE (MICA, n=832), were used for development and external validation of this risk assessment model.

In the CATS cohort, a penalized likelihood regression was used to select predictive variables from a broad set of clinical and laboratory factors, which led to a final model including two variables, the tumor site category (hazard ratio (HR) per 1 category increase=1.96, 95%CI: 1.41-2.72, p=0.0001), and D-dimer (HR per doubling=1.32, 1.12-1.56, p=0.001). The model discriminated well between cancer patients with and without VTE (C-Index=0.67, 95%CI 0.64-0.68) and was appropriately calibrated. As compared to the Khorana score, the new model correctly re-classified a significant proportion of patients according to their outcome (net reclassification improvement=0.44). In the external validation cohort (MICA study), the resulting nomogram demonstrated good discrimination (C-Index=0.66, 95% CI: 0.58-0.72) and good calibration.

This externally validated risk assessment model of only one clinical factor (tumor site) and one biomarker (D-dimer) predicted the risk of VTE in cancer patients, and has the potential to aid physicians in selecting appropriate patients for thromboprophylaxis.

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