The predictive value of alkaline phosphatase and lactate dehydrogenase for overall survival in patients with esophageal squamous cell carcinoma

The elevation of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) has been demonstrated to predict worse prognosis in various malignancies; however, their prognostic value in esophageal squamous cell carcinoma has not been well studied. We conducted a retrospective study of 906 patients with esophageal squamous cell carcinoma to explore their prognostic value for overall survival. The optimal cutoff points for ALP and LDH were determined. We analyzed the association between the levels of ALP and LDH and clinicopathological characteristics. Their prognostic value for overall survival was explored by univariate and multivariate analysis. We also proposed the ALP and LDH classification and examined its prognostic value in the general population and subgroups. The optimal cutoff points of ALP and LDH to predict overall survival were 90.7 and 361.5 U/L respectively. Higher levels of ALP and LDH were both associated with more advanced TNM stage (P = 0.003 and 0.002, respectively) and more distant metastasis (P = 0.001 and P < 0.001, respectively). Both ALP (≤90.7/>90.7 U/L) and LDH (≤361.5/>361.5 U/L) were independent prognostic factors for overall survival in esophageal squamous cell carcinoma (P = 0.004 and P < 0.001 by multivariate analysis). The ALP and LDH classification categorized patients into three subgroups with distinct prognosis (P < 0.001 by multivariate analysis) and identified a small group of patients who had extremely poor overall survival with a median of 4.2 months. In conclusion, ALP and LDH were both independent prognostic factors for overall survival. A combination of the two indexes might contribute to further identification of survival differences in esophageal squamous cell carcinoma.