Incidence of venous thromboembolic disease (VTE) in a cohort of patients with colorectal cancer (CRC) according to KRAS, NRAS and BRAF status.

Abstract

e15136 Background: A recent study has suggested that KRAS mutation could increase the risk of VTE in patients with CRC. The role of others biomarkers, such as BRAF, in this setting is unknown. The aim of this study is to analyze the incidence of cancer-associated thrombosis in a cohort of patients with CRC based on KRAS, NRAS and BRAF status. Methods: We performed a retrospective review of patients with metastatic CRC and KRAS/NRAS/BRAF status known, attended in the Medical Oncology Department of the Hospital General Universitario Gregorio Marañón (Madrid, Spain) between January 2010 and January 2018. Results: 194 patients were identified and included in the analysis. The median age was 64 years (18-86). Most were metastatic at diagnosis (58.1%). Khorana’s predictive model: low-risk 67.7%, intermediate-risk 31.0%, high-risk 2.3%. The median follow-up was 35 months (2-240). 41 patients (21.1%) experienced VTE (11 pulmonary embolism, 15 lower extremity deep-vein thrombosis, 12 visceral vein thrombosis, 2 catheter-related thrombosis, 1 unknown). Most had metastatic disease at the moment of VTE (90.2%). 40% of the events occurred at the time of diagnosis or within the first 6 months. 65% were incidental events. Khorana’s predictive model in VTE patients: low-risk 63.4%, intermediate-risk 24.5%, high-risk 7.3%. According to biomarkers, the incidence was 19.1% (13/68) in KRAS/NRAS mutated patients, 28.6% (6/21) in BRAF mutated patients and 21% (22/105) in triple-wild-type patients. 6/38 patients (15.8%) developed recurrent thrombosis. In the univariate analysis, the presence of chronic kidney disease (p = 0.022), ECOG ≥ 2 (p = 0.038) and high-risk Khorana score (p = 0.011) were significantly associated with increased risk of VTE. Metastatic disease showed a trend towards the statistical significance (p = 0.053). In the multivariate model, including this variables, age, sex and biomarkers, only ECOG ≥ 2 remained independent predictor of VTE (OR 8.73; CI 95% 1.32-57.82; p = 0.025). Conclusions: The biomarkers have not been associated with the risk of VTE. We have observed a high incidence of VTE in BRAF mutated patients that should be investigated in further studies.