Perineural Invasion in Oral Cavity Squamous Cell Carcinoma Does Not Affect Survival

Abstract

Objectives: 1) Determine if the presence of perineural invasion (PNI) affects survival in oral cavity cancer patients. 2) Determine what factors affect survival in oral cavity cancer patients. Methods: We performed a retrospective review of patients who underwent surgical resection with or without a neck dissection for treatment of primary oral squamous cell carcinoma from January 1, 2000, to December 31, 2009. Data were extracted from the institute’s cancer registry and the electronic medical record. Univariate and multivariate analysis were used to test the significance of pathologic characteristics including: PNI, extra-capsular extension, site, and positive surgical margin on survival. Results: 443 patients were identified, and 374 patients fit selection criteria. Mean age at diagnosis was 60.9 years. 59.1% were male. PNI was present in 38.5% and positive surgical margin in 28.3%. Patients with PNI had poorer disease specific survival rate than those without (p=0.001) (5-year survival, 64.4% vs 79.8%). Univariate analysis found that patients with PNI ( P < 0.001), palate site ( P = 0.013) (sub-sites were compared to all other cases of oral cavity cancer), retromolar trigone site ( P = 0.015), positive margins ( P = 0.013), and extra-capsular extension ( P < 0.001) had significantly worse survival. Those patients who had tumors of the gums ( P = 0.013) had significantly better survival. Multivariate analysis found that patients with tumors of the palate ( P =0.12), extra-capsular extension ( P = 0.004), and positive surgical margins (p=0.004) had significantly worse survival. Those with tumor of the gums ( P = 0.006) had significantly better survival. Conclusion: The presence of perineural invasion in oral cavity squamous cell carcinoma does not independently affect survival.