Salivary Sialic Acid Levels as a Biomarker for Early Detection of Oral Precancer and Oral Cancer: Systematic Review...

Salivary sialic acid (SSA) has been detected as biomarker in several cancers and the level of salivary sialic acids has been proven to have a potential diagnostic value in early detection of cancer.  This systematic review aims to assess Salivary Sialic Acid (SSA) levels as a biomarker for early detection of oral precancer and oral cancer.

A comprehensive Literature search was conducted in various databases such as PubMed, Scopus, Google scholar and ProQuest. Quality assessment of articles was done by Newcastle Ottawa Quality Assessment Scale.

A total of 22 studies were included in the systematic review and 14 articles were included for meta-analysis. Studies showed an increase in SSA levels in both oral precancer (SMD 1.79; 95% CI 0.41-3.18), and oral cancer (SMD 11.30; 95% CI -17.04 - 39.64). Total free and protein-bound sialic acid levels were increased in oral cancer group as compared to the healthy controls. The overall standard mean difference of FSA, PBSA, TSA among oral cancer and HC (SMD 23.83; 95% CI 9.22-38.44; p=0.02) and the data revealed statistically significant differences. The results of Meta-analysis revealed statistically significant differences between SSA levels of oral cancer and healthy group.

Salivary sialic acid levels were observed to be consistently higher in oral cancer group compared to oral precancer and healthy group. However, a cut-off value of SSA levels for the early detection of oral cancer and precancer could not be established because of the limited and heterogeneous data. In order to translate the use of SSA levels into clinical practice, to utilize it as a sensitive and reliable biomarker, more standardized method of saliva processing and biochemical analysis are required with studies conducted on larger populations.