Prognostic impact of perineural invasion in early stage oral tongue squamous cell carcinoma: Results from a prospective randomized trial

Background: Although perineural invasion (PNI) has been recognized as a poor prognostic factor for oral cancer, few studies have focused on tongue squamous cell carcinoma (TSCC). Using a prospective randomized trial, this study investigated the role of PNI in the regional control and survival of the patients with cT1-2N0 TSCC, and clarified the benefit of neck management based on PNI status. Methods: PNI status was reviewed under H&E staining in tumors of 221 patients with cT1-2N0 TSCC, who were randomly assigned into elective neck dissection (END) group (n = 111) and observation group (n = 110). Oncologic and survival outcomes were analyzed by multivariate regression and Kaplan-Meier analyses. Results: PNI was identified in 34 patients and multivariate analyses revealed that PNI remained an independent predictor for cervical lymph node metastasis (CLNM), local relapse, neck relapse and disease-specific survival (DSS) after controlling for T stage and pathologic differentiation. END could not improve the benefit for patients. Stratified analysis revealed that END also could not improve neck control or DSS among patients with PNI. Conclusions: This study demonstrated that PNI was an invaluable pathological parameter to independently predict cervical metastasis, local relapse, neck relapse and poor survival outcomes, but END could not improve benefits compared to observation for the PNI-positive patients. (C) 2018 Elsevier Ltd. All rights reserved.