A modified Khorana risk assessment score for venous thromboembolism in cancer patients receiving chemotherapy: the Protecht score

TLDR: A modified Khorana risk assessment score is designed by adding platinum or gemcitabine-based chemotherapy to the predictive variables already taken into account in the Khoranas, and the effect of nadroparin for VTE prophylaxis is assessed according to theKhorana and Protecht scores.

Abstract: The association between cancer and venous thromboembolism (VTE) is well established [1]. Indeed, up to 20 % of cancer patients have a symptomatic VTE, which is recognized to be one of the leading causes of death in these patients [2]. Patients with cancer are heterogeneous concerning the risk for VTE. Some solid malignancies including pancreatic, lung, colon-rectum, ovarian, and brain cancer are associated with a particularly high risk for VTE. A risk assessment score for VTE, known as Khorana score, was validated for cancer patients treated with chemotherapy in order to identify high risk patients [2]. Among cancer patients receiving chemotherapy, rates of VTE seem to be particularly high in those receiving cisplatin or carboplatinbased chemotherapy as well as gemcitabine [3]. We designed a modified Khorana risk assessment score (the Protecht score) by adding platinum or gemcitabine-based chemotherapy to the predictive variables already taken into account in the Khorana score. The role of antithrombotic prophylaxis in cancer patients receiving chemotherapy is currently an area of active investigation. Recently, in the Protecht (PROphylaxis of ThromboEmbolism during CHemoTherapy) study, a 50 % risk reduction in the incidence of thromboembolic complications is associated with nadroparin in these patients (NCT 00951574) [4]. The need for VTE risk assessment in cancer patients receiving chemotherapy has been emphasized in the most recent oncology guidelines [5] to optimize the benefit of antithrombotic prophylaxis in this setting. The aims of this analysis were: (1) to evaluate the Protecht score, in comparison with the Khorana score, for identifying high risk cancer patients in a post hoc analysis of the placebo group of the Protecht study, and (2) to assess the effect of nadroparin for VTE prophylaxis according to the Khorana and Protecht scores. The Khorana predictive score assigns 2 points to very high risk cancer sites (pancreatic or gastric) or 1 point to high risk cancer sites (lung, ovarian or bladder). In addition, 1 point is assigned for each of the following: platelet count C350 9 10/L, hemoglobin B10 g/dL, or use of erythropoietin-stimulating agents, leukocyte count C11 9 10/L and body mass index C35 kg/m. The assigned point for each variable included in the risk model was calculated on bases of the regression coefficients obtained from the derivation model. In the Protecht predictive score, treatment with cisplatin or carboplatin-based chemotherapy or gemcitabine adds 1 point and the association 2 points to the score based on the five predictive variables of the Khorana score. The assigned point for each variable was based on the estimation of risk as extrapolated from the literature. For the purpose of this analysis, the group of high-risk patients was identified by a score C3, whereas patients with a score between 0 and 2 were considered at low-intermediate risk for VTE. For the Protecht investigators.