Pretreatment Serum Lactate Dehydrogenase Level as an Independent Prognostic Factor of Nasopharyngeal Carcinoma in the Intensity-Modulated Radiation Therapy Era

BACKGROUND The aims of this study were to analyze the prognostic value of baseline lactate dehydrogenase (LDH) among nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiation therapy (IMRT), and to evaluate the potential application of LDH in monitoring treatment efficacy dynamically. MATERIAL AND METHODS From June 2005 to December 2010, 1188 patients with non-metastatic NPC who underwent IMRT with or without chemotherapy were reviewed. Univariate and multivariate analyses were performed to evaluate the predictive value of baseline LDH. Wilcoxon signed-rank test was used to analyze the difference between baseline and post-radiotherapy LDH, and to compare post-radiotherapy LDH with the LDH in cases of distant failure. RESULTS Patients with elevated LDH had significant inferior survival rates, in terms of overall survival (70.0% vs. 83.2%, p=0.010), disease-specific survival (71.1% vs. 85.7%, p=0.002), and distant metastasis-free survival (71.1% vs. 83.4%, p=0.009), but not correlated with locoregional relapse-free survival (p=0.275) or progression-free survival (p=0.104). Subgroup analysis demonstrated that this predictive effect was more significant with advanced stage. Sixty-five post-radiotherapy LDH levels were available from the 90 patients with high LDH at initial diagnosis, and these levels fell in 65 patients, with 62 cases (95.4%) falling within the normal range. Of the 208 patients who experienced distant metastasis, 87 had an available LDH level at that time. Among them, 69 cases (79.3%) had an increased level compared with the post-radiotherapy LDH level. CONCLUSIONS Pretreatment LDH is a simple, cost-effective biomarker that could predict survival rates and might be used in individualized treatment. It is also a potential biomarker that might reflect tumor burden and be used to monitor therapy efficacy.