Prognostic value of plasma d-dimer levels in patients with glioblastoma multiforme - Results from a pilot study.

Glioblastoma multiforme (GBM), the most common primary tumor of the central nervous system, is associated with a state of hypercoagulability. We hypothesized that tumor activity is displayed by elevated d-dimer plasma levels and that d-dimer might be used as a predictor of survival in patients with glioblastoma multiforme. We studied effects on clinical outcomes of d-dimer levels obtained two to three weeks following histologic confirmation of the diagnosis of GBM at surgery or needle biopsy, but prior to chemotherapy or radiation therapy, in 23 patients. During a median follow-up of 7.3 months (interquartile range 3.5 to 22 months), we observed a total of 21 deaths (91.3%). Elevated d-dimer levels were significantly associated with mortality compared to normal values (log rank p = 0.002). The adjusted hazard ratio for death in patients with elevated d-dimer levels was 10.8 (95% confidence interval, 1.3 to 93.1; p = 0.03), compared to controls. Similar effect sizes were revealed when analyzing the association between progression-free survival and d-dimer levels (log rank p = 0.002). Additionally, patients with elevated d-dimer levels were more likely to suffer from venous thromboembolism compared to patients with normal values (log rank p = 0.025). Our data support the assumption that d-dimer levels are related to adverse outcome in patients with GBM. However, our results need to be confirmed by a large, prospective cohort study.