In a study published by Wolpert et al in the European Journal of Cancer, venous thromboembolic events (VTE) were reported in 12% of a cohort of patients with cancer that had metastasized to the brain. Researchers identified thrombogenicity of primary tumor, immobilization, chemotherapy, obesity, and steroid use as factors independently associated with VTE and developed a score model known as PICOS. The team reported that the PICOS score was superior to established risk models for VTE risk estimation in patients with cancer.
Study Background and Methods
According to the study authors, VTE represents a significant complication in patients with systemic malignancies. In patients with brain metastasis, risk of thrombosis is poorly defined. Furthermore, available risk calculation scores are not validated in this population.
The authors identified 811 patients with brain metastasis. They retrospectively reviewed electronic charts for the occurrence of VTE. Furthermore, they reviewed risk factors, which were tested in univariate and multivariate analyses and finally integrated in a score model for risk estimation. For the validation phase, an independent cohort of 346 patients with brain metastasis was available.
Of a total of 811 patients included in the analysis, incidence of VTE was documented in 97 (12.0%). The study team confirmed that primary tumors with high thrombogenicity (hazard ratio [HR] = 1.7, 95% confidence interval [CI] = 1.1–2.8, P = .02), treatment with dexamethasone (HR = 2.27, 95% CI = 1.5–4.5, P = .011), use of chemotherapy (HR = 3.4, 95% CI = 1.6–7.5, P = .005), a body mass index of > 35 kg/m2 (HR = 3.4, 95% CI = 1.6–7.5, P = .002) and immobilization (HR = 2.4, 95% CI = 1.3–4.3, P = .003) were parameters independently associated with VTE.
The authors derived a score model for VTE risk estimation—PICOS—based on these identified risk factors, with a possible score of 0 to 7 points. They ran receiver-operating characteristic curve analysis which demonstrated its prognostic accuracy (area under the curve [AUC] = 0.71, 95% CI = 0.64–0.77). Its value for the evaluation of VTE risk was superior to that of other scores such as the Khorana (AUC = 0.51) or CONKO (AUC = 0.52) scores. The potential value of the PICOS score was confirmed in the validation cohort (AUC = 0.72, 95% CI = 0.63–0.82).
The study authors concluded, “The PICOS score may become a helpful tool for the identification of patients with brain metastasis at high risk for VTE and for stratification in controlled studies.”
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