Salivary Neutrophil-to-Lymphocyte Ratio as a Prognostic Predictor of Oral Premalignant and Malignant Disorders: A Prospective Study.

Abstract

Inflammation is a definitive characteristic of carcinogenesis. The neutrophil-to-lymphocyte ratio (NLR) is an easy and efficient indicator of inflammation and a valuable marker in individuals with malignancies. The present study was performed to ascertain NLR values in salivary samples collected from individuals with oral premalignant disorders (OPMDs) and to assess the prognostic significance of NLR in distinguishing OPMDs from oral malignancies. This study was conducted on 50 patients histopathologically diagnosed with OPMDs with mild dysplasia. The patients were provided with standard medicinal treatment, encouraged to quit their habits, and followed up for one year at three-month regular intervals. During the follow-up, 29 (67.4%) patients completely recovered, whereas 14 (32.6%) developed oral malignancies. Salivary samples were collected at baseline (T0) and one-year follow-up (T1). The total salivary neutrophils and lymphocytes were counted using an improved cell counting method with a Neubauer chamber. The NLR values were calculated at T0 and T1. The paired t-test was used to compare the NLR values at T0 and T1. The cutoff value of the NLR was determined using the receiver operating characteristic (ROC) curve. The Youden index was used to determine the optimal cutoff NLR values in the groups. Statistical significance was set at p ≤0.05. OPMDs were predominantly observed in males, with leukoplakia being the most prevailing one. Erythroplakia exhibited the highest propensity for malignant transformation, and habitual consumption of alcohol and tobacco was identified as a risk factor for this transformation. NLR increased in both premalignant and malignant conditions. NLR value equal to or exceeding 4 was determined to be a reliable indicator for the occurrence of oral cancer in patients with OPMDs. The ROC curve analysis yielded a sensitivity and specificity of 92%, with an area under the curve (AUC) of 0.928. The poor prognosis of oral cancers was associated with higher NLR values. NLR values in salivary samples can serve as an independent reliable predictor in oral cancer and OPMDs.