Pre-treatment Serum Lactate Dehydrogenase is Predictive of Survival in Patients with Nasopharyngeal Carcinoma Undergoing Intensity-Modulated Radiotherapy.

Objective: To analyze the prognostic value of pre-treatment serum lactate dehydrogenase (SLDH) level in patients with nasopharyngeal carcinoma (NPC) receiving intensity-modulated radiotherapy (IMRT) with or without chemotherapy. Methods: From January 2010 to March 2013, 427 eligible patients were reviewed. Pre-treatment SLDH level was measured within 2 weeks prior to treatment. Receiver operating characteristic (ROC) curve analysis was performed to select the optimal cutoff point. The impact of pre-treatment SLDH on overall survival (OS), progression-free survival (PFS) and distant metastasis-free survival (DMFS) were analyzed using Kaplan-Meier method and Cox proportional hazards model. Further propensity score matching was carried out to adjust bias. Results: The optimal cutoff point of 168.5 IU/L was selected based on ROC curve analysis. Multivariate analysis showed that high pre-treatment SLDH level was an independent prognostic factor for OS (P=0.001), PFS (P=0.004) and DMFS (P=0.001). After propensity score matching was performed, it remained to be significantly associated with poor OS (P=0.009), PFS (P=0.015) and DMFS (P=0.008) in the adjusted model. Conclusion: High pre-treatment SLDH level predicts poor survival in patients with NPC treated with IMRT-based therapy. As a routinely performed biomarker, pre-treatment SLDH can be utilized in combination with current Tumor-Node-Metastasis staging to predict survival and to plan a personalized treatment in these patients.