D-Dimer, but not the Khorana score predicts venous thromboembolism in lung cancer patients

E. Grilz, O. Königsbrügge, J. Riedl, J. Thaler, R. Pirker, C. Ay, I. Pabinger (Vienna, Austria)

Vascular Wall, Platelets and Acquired Problems
Date: 16.02.2017,
Time: 14:00 - 15:15

Objective: Patients with lung cancer frequently suffer from venous thromboembolism (VTE). The Khorana-Score was introduced in 2008 to assess the risk of VTE in cancer patients and to identify patients who may benefit from primary prophylaxis with anticoagulation. Previous studies have shown that elevated D-dimer levels are associated with an increased risk of VTE in cancer patients.

Methods: In this prospective observational study we investigated, if the Khorana Score can predict VTE in lung cancer patients. We also examined, if a dichotomized D-dimer can predict VTE in newly diagnosed lung cancer patients. The 75th percentile (1.77 µg/mL) of D-dimer in the lung cancer population was defined as the cut-off. The Khorana Score is calculated based on the type of cancer, the body mass index (BMI), and the complete blood count. The endpoints of the study were objectively confirmed VTE with diagnostic imaging and adjudicated by an independent committee. Competing-risks regression according to Fine and Gray was used to calculate the risk and distinguish between high- and low risk of VTE.

Results: From Oct. 2003 to Apr. 2014, 320 lung cancer patients (60.3% male; mean age: 61 years) were included in the study. 28 (8.8%) patients developed VTE within 2 years. The median observation time was 370 days, and 198 (61.9%) patients died during the observation time. The Khorana-Score did not predict VTE in lung cancer patients, the subdistribution hazard ratio (SHR) was 0.3 (95% Confidence Interval [CI]: 0.1 – 1.1) in patients with a Khorana Score of two, and 0.7 (95% CI: 0.2 – 2.5) in patients with a score of three or higher. D-dimer was significantly associated with the occurrence of VTE in lung cancer patients; the SHR was 2.82 (95% CI: 1.32 – 6.03) after adjusting for age and sex. The cumulative probabilities of VTE occurrence were 12.5% and 16.3% in patients with D-Dimer above the 75th percentile, respectively after 180 and 365 days, and 2.92% and 5.4% in those below the 75th percentile (Figure 1).

Conclusion: D-dimer independently predicts VTE in lung cancer patients. The Khorana-Score does not distinguish between lung cancer patients with high- and low risk for VTE.