Prognostic Implications of Neutrophil to Lymphocyte Ratio (NLR) in Esthesioneuroblastoma

Introduction: Esthesioneuroblastoma (ENB), or olfactory neuroblastoma, is a rare sinus neoplasm that arises from the olfactory neuroepithelium. This tumor is frequently associated with extensive growth and invasion of the skull base, anterior fossa, and orbits. ENB is evaluated according the Kadish radiologic staging system and the Hyams histologic grading system. The current treatment protocol includes primary surgical resection with adjuvant radiotherapy and chemotherapy for extensive or high-grade malignancy. Neutrophil-to-lymphocyte ratio (NLR) is a biomarker that is associated with inflammation and has been correlated with worse prognosis in certain tumors.

Methods: Retrospective chart review was performed of all patients treated for initial presentation of ENB at our institution from 2004 to 2020. NLR was calculated from preoperative CBC, and each patient was evaluated for Kadish staging, Hyams grade, intraoperative positive margin, adjuvant therapy, post-treatment recurrence, and death. Statistical analysis was conducted using R (Version 4.1.2). To assess the impact of covariates on the Kadish staging and Hyams grade, a mixed-effects model for three-level ordinal response data was utilized. For the models with intraoperative margin positivity, use of adjuvant therapy, post-treatment recurrence, and death as the dependent variable, binomial logistic regression for binary outcomes was utilized.

Results: 45 patients met inclusion criteria with an average follow-up of 9.3 years. NLR was found to be significantly associated with Kadish Stage (p value < 0.0001). More specifically, an increase from Kadish Stage A to Kadish Stage C corresponded to a 3.74 times increase in the NLR. Furthermore, NLR was found to be a statistically significant predictor of a positive tumor margin (p-value = 0.04), with an increase of 2.6 in NLR when compared to tumors with negative margins. There was no significant association between NLR and Hyams stage, use of adjuvant therapy, post-treatment recurrence, or patient death.

Conclusions: Elevated NLR in ENB is associated with higher Kadish grade and intraoperative positive margin.