Prognostic Significance of Neutrophil-Lymphocyte Ratio in Salivary Gland Neoplasms: A Systematic Review.

ImportanceSalivary gland tumors (SGTs) are rare and heterogeneous, necessitating improved prognostic tools to optimize patient management.ObjectiveTo evaluate the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) in distinguishing between benign and malignant SGTs, identifying tumor stage, and predicting survival and adverse events.DesignSystematic review conducted according to PRISMA guidelines.SettingPublished clinical studies from tertiary care centers and academic hospitals globally, retrieved from electronic databases (PubMed/MEDLINE, Embase, and Cochrane Library).ParticipantsIncluded studies focused on adult and pediatric patients with histologically-confirmed SGTs. Eligibility criteria encompassed all original research articles reporting NLR values related to diagnosis or prognosis of SGTs.ExposureThe exposure of interest was the NLR, evaluated pretreatment in relation to tumor type (benign vs malignant), tumor stage, survival, and adverse treatment outcomes.Main Outcome MeasuresPrimary outcome: prognostic performance of NLR regarding overall survival and disease stage.ResultsSeventeen original studies were included, with a median cohort size of 123 patients (range: 20-1989). The mean NLR was 2.86 for distinguishing benign versus malignant SGTs, 2.23 for early-stage versus late-stage malignancy, and 3.62 across different malignant histologic subtypes. An NLR below the cutoff value of 2.51 was significantly associated with improved overall survival ( < .05). A higher cutoff of 3.95 correlated with the presence or absence of grade ≥3 adverse events ( < .05).ConclusionsNLR shows promise as a cost-effective, noninvasive biomarker to stratify malignancy risk, assess tumor stage, and predict prognosis and treatment-related toxicity in both adult and pediatric SGT populations.RelevanceThese findings support the integration of NLR into routine pretreatment evaluation protocols for SGTs. Future prospective, multicenter studies are necessary to validate standardized cutoff values for clinical use and to further investigate its role in personalized treatment strategies.