The Role of Blood Inflammatory Markers in Salivary Gland Carcinoma: A Scoping Review

Background/Objectives: Malignant carcinomas of the salivary glands account for approximately 1 to 7% of all head and neck malignancies and approximately 0.3% of all malignant neoplasms. Recently, the scientific community has focused on finding biomarkers that could tailor the treatment for patients with this type of cancer. The neutrophil–lymphocyte ratio (NLR) was the first marker studied and it is one of the most widely used; the platelet–lymphocyte ratio (PLR), the systemic immune inflammation index (SII) and the systemic inflammatory response index (SIRI) have recently emerged as important biomarkers. The aim of this scoping review is to evaluate the role of inflammatory biomarkers in the management of salivary gland malignancies. Methods: A review of the English literature on inflammatory blood markers in major salivary gland cancer was performed using PubMed, Scopus, and Google Scholar databases. The literature review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines for scoping reviews. Results: Eleven full-text articles were included in this review, for a total of 1356 patients in which the role of inflammatory biomarkers (NLR, PLR, SII or SIRI) for the diagnosis and prognosis of salivary gland cancer was assessed. NLR (i) was evaluated in all the studies; (ii) it contributed to the diagnosis and prognosis of both adult and pediatric patients and (iii) can be considered the main biomarker, even if a universal cut-off range is not available yet. PLR, SII and SIRI were introduced more recently and were evaluated only in some studies. Conclusions: The findings of this study suggest that elevated NLR values, regardless of age, are more frequently associated with malignancy and a poor prognosis. Further studies are necessary to evaluate the role of biomarkers other than NLR, and to identify universal and practical cut-off values.