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Background: Salivary gland tumors are rare, comprising only 6%-8% percent of all head and neck neoplasms. Most are benign and commonly occur in the parotid gland. In the last decade elevated hematological inflammatory parameters, such as neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) were identified as predictive and prognostic factors in various malignancies. The aim of this study was to evaluate the differences in preoperative NLR and PLR in benign and malignant salivary gland tumors.
Methods: This retrospective study included a total of 133 patients (28 malign, 105 benign) with salivary gland tumors (age range: 17-89 years; 68 male and 65 female) who were treated between January 2006 and May 2016. Preoperative counts and levels of hematological parameters were obtained from the recorded computerized database of benign and malignant tumors.
Results: NLR and PLR levels were significantly higher in the malignant salivary gland tumor group than the benign group. (Mean NLR: 2.74 ± 1.183 vs 2.039 ± 0.791 [p: 0.001]; Mean PLR: 160361.02 ± 16200.293 vs 124669.76 ± 4308.446 [ p: 0.014]). According to the receiver operating curve (ROC) analysis of the NLR, the area under the curve (AUC) was 0.705 [(95% CI 0.589–0.821); p : 0.001] with a cutoff value 2.13 with 75% sensitivity; 61% specificity. ROC analyses performed for PLR with a cutoff value of 126794 had 64% sensitivity and 44% specificity and AUC was found to be 0.651 [(95% CI 0.541- 0.760); p:0.014].
Conclusions: Results of the current study revealed the potential predictive role of NLR and PLR in patients with salivary gland tumors. These cheap and easily available blood count parameters could be useful biomarkers in the future. Further investigations are needed to confirm these findings.