The role of perineural invasion in treatment decisions for oral cancer patients: A review of the literature

Purpose: The role of perineural invasion (PNI) in the management of patients with oral squamous cell carcinoma (OSSC) is still controversial, and there is no consensus regarding the most appropriate therapeutic approach. The purpose of this study is to review the findings in the literature describing OSCC as a neurotropic malignancy, with the aim of correlating perineural invasion with treatment decisions and disease prognosis. Materials and methods: A literature search was conducted of references based on the MEDLINE and Cochrane Database of Systematic Reviews, with subject keywords including four main categories: perineural invasion, perineural spread, oral squamous cell cancinoma, neurotropic carcinoma. Results: In this systematic review and analysis, more than 350 publications met the eligibility criteria of the authors. Conclusion: Perineural invasion (PNI) is a widely recognized indicator of poor prognosis in oral cancer patients, strongly correlating with aggressive tumor behavior, disease recurrence, and increased morbidity and mortality. Elective neck dissection could be an indicator in improving neck control in PNIpositive patients, while the addition of adjuvant postoperative radiotherapy may not significantly improve survival rates. Various molecular markers have been correlated with perineural tumor spread, but further investigations are required before targeting PNI as part of advanced cancer therapies. (C) 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.