Elevated Serum Endostatin Levels are Associated with Poor Survival in Patients with Advanced-stage Nasopharyngeal Carcinoma

Abstract

AimsTo evaluate the prognostic value of serum endostatin levels in patients with advanced-stage nasopharyngeal carcinoma (NPC). Materials and methodsBetween August 2003 and March 2005, 218 patients with advanced-stage NPC were enrolled in this study, including 70 patients in the training cohort and 148 in the validation cohort. The pre-treatment serum endostatin and vascular endothelial growth factor (VEGF) levels were measured using competitive enzyme immunoassays. For the normal control, serums samples from 20 healthy individuals were also collected. ResultsSerum endostatin levels in the patients with advanced-stage NPC were significantly higher than those of controls, but VEGF levels were similar in the two groups. Univariate analysis revealed significant differences between the high and low endostatin level groups regarding 5 year overall survival (63.9% versus 90.5%; P = 0.003), progression-free survival (PFS) (50.2% versus 79.3%; P = 0.003) and distant metastasis-free survival (DMFS) (59.1% versus 85.3%; P = 0.01) in the training cohort. Using the same cut-off value generated from the training cohort, there were also significant unfavourable correlations between serum endostatin levels and overall survival (P = 0.001), PFS (P = 0.001) and DMFS (P = 0.002) in the second independent validation cohort. Multivariate analysis using the entire group (n = 218) revealed that the serum endostatin level was an independent unfavourable prognostic factor for overall survival (hazard ratio 4.8; 95% confidence interval 2.48–9.23; P < 0.0001), PFS (hazard ratio 3.44; 95% confidence interval 2.06–5.74; P < 0.0001) and DMFS (hazard ratio 3.65; 95% confidence interval 1.92–6.94; P < 0.0001) in patients with advanced-stage NPC. No associations were observed between the outcomes and the serum VEGF levels in patients with advanced-stage NPC. ConclusionsHigh endostatin levels are associated with poor survival and this knowledge may improve the risk stratification of patients with advanced-stage NPC.