Abstract
Background: Previous studies have reported that the albumin-to-alkaline phosphatase ratio (AAPR), a novel blood biomarker-based index, is associated with clinical outcome in several cancers. However, data relating to lung cancer are rare. This study was performed to clarify the clinical significance of AAPR in patients with metastatic non-small-cell lung cancer (NSCLC). Methods: In total, 290 stage IV NSCLC patients were enrolled in this retrospective study. Associations between serum enzyme levels and clinical characteristics were analyzed using the Mann-Whitney U-test or chi-squared test. Kaplan-Meier survival analysis and Cox's proportional hazard regression model were adopted to assess the prognostic value of AAPR for overall survival (OS). Results: The optimal cut-off points for AAPR and lactate dehydrogenase (LDH) were 0.36 and 265.5 U/L, respectively. Patients with AAPR ≤0.36 had apparently longer survival than those with AAPR >0.36 (13 vs 7 months, P<0.001). Furthermore, AAPR was an independent predictor of OS in metastatic NSCLC in multivariate analysis (HR=0.657, 95% CI=0.504-0.856, P<0.01). The prognostic impact of LDH for survival of NSCLC populations was also validated in this study (HR=1.462, 95% CI=1.070-1.999, P<0.05). Conclusion: Elevated AAPR can be an independent favorable prognostic indicator in metastatic NSCLC.