Serum Lactate Dehydrogenase Enzyme as a Tumor Marker in Potentially Malignant Disorders: A Systematic Review and Meta–Analysis

BACKGROUND: Oral cancer is often preceded by Potentially Malignant Disorders (PMDs) and important role of biochemical markers for early diagnosis has been well documented; however, there is limited evidence of Serum lactate dehydrogenase (SLDH) as an effective biochemical marker in diagnosis of PMDs. The present meta-analysis was conducted to assess if serum LDH can be a used as standard biomarker for PMDs and consequently aid in diagnosis of oral cancer. METHODS: A comprehensive search was conducted in Medline, Scopus, Web of Science, EBSCO host, Cochrane databases and Google Scholar for studies evaluating estimation of SLDH in PMDs. Search strategy included all types of studies evaluating level of SLDH in patients with PMDs. PRISMA guidelines were followed for the meta-analysis. Fixed-effects model was used to assess the mean differences in SLDH levels between healthy controls and PMDs. RESULTS: A total number of nine studies were included in meta-analysis after screening for inclusion and exclusion criteria. Potentially malignant disorder was significantly associated with increased serum LDH level compared to healthy controls (pooled SMD: 1.83 (95% CI, 1.52, 2.15) (P < 0.00001; Subgroup analysis of OSMF (Oral Submucous Fibrosis) studies showed significant association with increased serum LDH level compared to healthy controls (pooled SMD: 2.57 (95% CI, 2.16, 2.98; P < 0.00001). Sensitivity analysis for the five studies reflected a significant reduction in I(2) values to 24 % (P=0.26). Funnel plots were derived for any evidence of publication bias among the studies. CONCLUSION: Meta-analysis suggests that SLDH is increased in potentially malignant disorders compared to healthy controls. The results of this metanalysis should encourage use of SLDH as a biomarker in diagnosis of PMDs.