Elevated plasma big ET-1 is associated with distant failure in patients with advanced-stage nasopharyngeal carcinoma

BACKGROUND. Endothelin-1 (ET-1) is a potent vasoactive peptide and a hypoxiainducible angiogenic growth factor associated with the development and spread of solid tumors. The clinical significance of plasma big ET-1 in patients with advanced-stage nasopharyngeal carcinoma (NPC) is not known. METHODS. Pretreatment plasma big ET-1 levels were measured in 62 patients with advanced-stage NPC using a sandwich enzyme-linked immunoassay and compared with the levels from a control group (n = 19 participants). RESULTS. The median pretreatment plasma big ET-1 level in patients with advanced-stage NPC was 4.6 pg/mL, (range, 1.9-15.2 pg/mL) and was significantly elevated compared with median plasma big ET-1 levels in healthy controls, 2.6 pg/mL (1.6-4.5 pg/mL) (P <.001). Using the upper limit (4.5 pg/mL) of control subjects as the cut-off value, plasma big ET-1 was <= 4.5 pg/mL in 29 (46.8%) patients and > 4.5 pg/mL in 33 (53.2%) patients. A pretreatment plasma big ET-1 level > 4.5 pg/mL was associated with a significantly poorer 2-year distant metastasis-free survival rate (56.7% vs. 81.1%, P =.031). Multivariate analysis showed that N classification (hazard ratio [HR], 2.416; 95% confidence interval [CI], 1.0715.447; P =.034) and pretreatment plasma big ET-1 level (HR, 3.151; 95% CI, 1.099-9.028, P =.033) were independent significant prognostic factors for post-treatment distant failure ill patients with advanced-stage NPC. CONCLUSIONS. Pretreatment plasma big ET-1 levels may be useful ill predicting post-treatment distant failure in patients with advanced-stage NPC.