The prognostic role of the pre-treatment neutrophil to lymphocyte ratio (NLR) and tumor depth of invasion (DOI) in early-stage squamous cell carcinomas of the oral tongue

The appropriate surgical management of early-stage oral tongue squamous cell carcinoma (OTSCC) remains a debated topic. The aim of this study is to investigate the role of the pre-treatment neutrophil to lymphocyte ratio (NLR) and tumor depth of invasion (DOI) in predicting the presence of occult neck metastases in early-stage OTSCC. A retrospective analysis of patients affected by early-stage (cT1-T2 cN0) OTSCC who were submitted to elective neck dissection (END) was performed. Tumors were classified retrospectively according to the 8th TNM classification, the DOI was assessed on the pre-operative magnetic resonance imaging, and the pre-treatment NLR was calculated for each patient. A logistic regression model to estimate the probability π (x) of cervical metastases by studying the NLR and DOI was carried out. Next, the correlation between the two variables, the NLR and DOI, was preliminarily studied. A cohort of 110 patients was analyzed (mean age, 62 years old; male to female ratio 1.2:1). The patients were staged as cT1 in 53 cases and cT2 in 57 cases. A DOI greater than 5.4 mm and a NLR greater than 2.93 are associated with an increased risk of presenting occult cervical metastases. Furthermore, the variables NLR and DOI are linearly associated with a positive correlation, proved by Spearman's rank correlation coefficient rho of 0.64, with a unitary increase in the DOI of 1 mm directly associated with an increase of 0.47 in the NLR. The DOI and NLR can be effectively used to predict the occurrence of occult neck metastasis and therefore to plan an END in early-stage OTSCC.