Venous thromboembolic events in glioblastoma patients: Common complication but not a major reason for death.

Abstract

e14530 Background: Venous thromboembolic events (VTE) are a major complication in cancer patients. Anticoagulant use is the appropriate treatment for acute VTE in cancer patients, although associated with increased risk for bleeding, especially in brain tumor patients. In glioblastoma patients it remains unclear whether occurrence of VTE is associated with survival and to what extent thromboprophylaxis is necessary and efficient. Methods: Frequency, risk factors, and treatment of VTE as well as its complications were assessed in an epidemiological glioblastoma cohort in the Canton of Zurich, Switzerland, in the years 2005 to 2014. Association of clinical data with survival were retrospectively analyzed using the log rank test. Results: Four-hundred-nineteen patients diagnosed with isocitrate dehydrogenase wildtype glioblastoma were identified in the 10-year time-frame. Median overall survival (OS) was 12.4 months (95% CI 11.4-13.4) with a median follow up of 64.5 months (95% CI 46.6-82.4).VTE were seen in 65 patients (15.7%; 5 patients with missing information on VTE).Median time from diagnosis of glioblastoma to occurrence of VTE was 2.0 months (95% CI 0.8-3.1). A history of VTE was found in 6 patients (9.2%). Thirty-nine patients were on steroids (62.5%; 1 patient with missing data) at time of diagnosis of VTE, and 35 patients (56%; 3 patients with missing data) had a Karnofsky Performance Score of less than 70%. At the time patients were diagnosed with VTE the majority of patients (93.8%) were treated with therapeutic anticoagulation. Complications resulting in stop of anticoagulation occurred in 11 patients (18.0%; 4 patients had no anticoagulation) mainly because of intracranial bleedings (9 patients). OS was not different (p = 0.355) between patients who were diagnosed with VTE and those who were not. Tumor progression (283 patients, 77.3%) was the major reason for death (366 patients with confirmed death) in this patient cohort, only 3 patients (0.8%) died because of confirmed VTE and another 5 patients (1.4%) had an unexpected sudden death. Conclusions: Although VTE was identified in 65 patients (16%) diagnosed with glioblastoma, VTE was no major reason for death. On a population-based level these data do not support the implementation of primary thromboprophylaxis in this cohort of patients.