CLINICOPATHOLOGICAL CORRELATION OF PERINEURAL INVASION AND ITS IMPACT ON SURVIVAL IN BUCCAL MUCOSA CARCINOMAS: A 4-YEARS PROSPECTIVE OBSERVATIONAL STUDY

Abstract

Background: Buccal mucosa squamous cell carcinoma is a common, aggressive oral malignancy in South Asia with variable survival influenced by histopathologic risk factors. Perineural invasion is linked to adverse outcomes in OSCC, but prospective buccal mucosa–specific evidence remains limited. Objectives: To assess the clinicopathological correlates of PNI and determine its impact on 12-month survival outcomes in patients with buccal mucosa carcinoma treated at a tertiary care centre. Methods: A prospective observational study included 30 consecutive patients (30–75 years) with biopsy-proven primary buccal mucosa SCC treated with curative intent at IMS & SUM Hospital, Bhubaneswar, from March 2022 to December 2025. Clinicodemographic, risk habit, imaging, staging, treatment, and histopathologic data were recorded. PNI was defined as tumour invasion of nerve sheaths or encirclement of ≥ one-third of the nerve circumference. Primary outcomes were 12-month OS and DFS, analysed using Kaplan–Meier, log-rank, and Cox regression. Results: PNI was identified in 12/30 (40.0%) patients. PNI positivity was significantly associated with DOI ≥ 10 mm (83.3% vs 33.3%, p=0.01), pN+ disease (66.7% vs 27.8%, p=0.04), and LVI (50.0% vs 16.7%, p=0.049). Twelve-month DFS was 50.0% in PNI-positive patient compared with specific 83.3% in PNI-negative patients (log-rank p=0.03). Twelve-month OS was 75.0% in PNI-positive vs 94.4% in PNI-negative patients (log-rank p=0.12). In a multivariable Cox model adjusting for DOI and pN status, PNI remained independently associated with poorer DFS (HR 3.10, 95% CI 1.02–9.39; p=0.046). Conclusion: PNI is common in buccal mucosa carcinoma and correlates with aggressive pathological features. In this prospective cohort (illustrative analysis), PNI was associated with significantly reduced DFS at 12 months. Routine PNI reporting and risk-adapted adjuvant therapy and surveillance are recommended.