Prospective study of circulating angiogenic markers in prostate-specific antigen (PSA)-stable and PSA-progressive hormone-sensitive advanced prostate cancer

Abstract

Objectives To prospectively describe and compare circulating vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in two groups of advanced prostate cancer patients undergoing androgen deprivation. The first patient group (n = 21) consisted of patients with stable serum prostate-specific antigen (PSA) and the second group (n = 20) consisted of patients with a rising serum PSA during androgen deprivation. Methods Patients with diabetes or active heart disease or those receiving anticoagulants were excluded. Circulating VEGF and bFGF were measured in platelet-poor plasma. bFGF was also measured in urine. Platelet factor 4 protein (PF4) assays were performed to evaluate platelet activity in platelet-poor plasma samples. Commercially available enzyme-linked immunosorbent assay kits were used for all assays, and all tests were performed in duplicate. Results The median age of this study population was 75 years (range 58 to 85). Median plasma VEGF measured in the PSA-stable group was 801.5 pg/mL and in the PSA-rising group was 655.5 pg/mL ( P = 0.464). Circulating bFGF was undetectable in plasma, but 4 patients in the PSA-stable group had measurable urine levels. Platelet-poor plasma PF4 assays in all patients were less than 3 IU/mL (normal range 0 to 10). Conclusions Our pilot study suggests elevated plasma VEGF levels in advanced prostate cancer do not increase during failure of androgen deprivation therapy. Most of the advanced cancer patients in this study expressed plasma VEGF. This suggests its potential role as a surrogate marker for response assessment during antiangiogenic therapy in this stage.