Prognostic significance of plasma vascular endothelial growth factor levels in patients with hormone-refractory prostate cancer treated on cancer andleukemia group B 9480

Purpose: Plasma vascular endothelial growth factor (VEGF) levels are signif icantly elevated in patients with hormone-refractory prostate cancer (HRPC) compared with patients with localized disease and have been associated wit h disease progression in other cancer patient populations. Therefore, we me asured VEGF levels in plasma prospectively collected from patients enrolled in Cancer and Leukemia Group B 9480, an intergroup study of suramin in pat ients with HRPC, to determine whether these levels had prognostic significa nce. Experimental Design: Pretreatment plasma was collected from patients with H RPC enrolled in Cancer and Leukemia Group B 9480, In a subset of samples re presentative of the entire cohort, plasma VEGF levels were determined in du plicate using a Quantiglo chemiluminescent ELISA kit (R&D Systems, Minneapo lis, MN). Statistical analyses were performed to determine the correlation between pretreatment plasma VEGF levels and time of overall survival. The p roportional hazards model was used to assess the prognostic significance of various cut points in multivariate models. Results: Plasma VEGF levels in this population ranged from 4-885 pg/ml, wit h a median level of 83 pg/ml, As a continuous variable, plasma VEGF levels inversely correlated with survival time (P = 0.002). Using various explorat ory cut points, plasma VEGF levels appeared to correlate with survival. In multivariate models in which other prognostic factors (serum prostate-speci fic antigen, alkaline phosphatase, evidence of measurable disease, and hemo globin) were included, plasma VEGF levels were significant at various cut p oints tested. Conclusion: Although these data are exploratory and need to be confirmed in an independent data set, they suggest that VEGF may have clinical signific ance in patients with HRPC.