Diagnostic Capability of Salivary Biomarkers in the Assessment of Head and Neck Cancer: A Systematic Review and Meta-analysis

The purpose of this systematic review and meta-analysis was to evaluate the diagnostic value of salivary biological markers in the diagnosis of head and neck carcinoma. Studies were gathered by searching Cochrane, EMBASE, LILACS, MEDLINE, and PubMed. The references were also crosschecked and a partial grey literature search was undertaken using Google Scholar. The methodology of selected studies was evaluated using the 14-item Quality Assessment Tool for Diagnostic Accuracy Studies. After a two-step selection process, 15 articles were identified and subjected to qualitative and quantitative analyses. The studies were homogeneous, and all had high methodological quality. Combined biomarkers demonstrated better accuracy with higher sensitivity and specificity than those tested individually. Furthermore, the salivary biomarkers reviewed predicted the early stages of head and neck carcinoma better than the advanced stages. A restricted set of five single biomarkers (interleukin-8, choline, pipecolinic acid, l-phenylalanine, and S-carboxymethyl-l-cysteine) as well as combined biomarkers demonstrated excellent diagnostic test accuracy. The present systematic review confirms the potential value of a selected set of salivary biomarkers as diagnostic tools for head and neck carcinoma.