Correlation of perineural invasion and histopathological features/clinical outcomes for carcinoma oral cavity: An analysis of 781 patients.

BACKGROUND

To evaluate the prognostic impact of perineural invasion (PNI) on oncological outcomes in oral cavity carcinoma patients.

METHODS

Chart review of 781 patients undergoing surgery for oral cavity carcinoma between 2013 to 2021 was done. All patients underwent surgery (per primum/post neoadjuvant chemotherapy) followed by adjuvant treatment as per histopathological report.

RESULTS

There were 653 male patients (83%) and the median age of the cohort was 48 years. Six hundred and thirty-two (80.8%) patients had locally advanced stage (III/IV). Three hundred and forty (44%) patients had PNI reported. PNI positivity correlated with higher pT stage, pN stage, overall stage and poor differentiation. Median follow-up was 51 months. At last follow-up, 571 patients (73%) were alive, of which 527 were disease free. Incidence of distant metastasis was significantly higher in patients having PNI (25% versus 13%, P = 0.001). On univariate analysis, patients with PNI-positive disease had significantly worse 5-year disease-free survival (DFS) (56% versus 68%, P = 0.001), locoregional control (LRC) (62% versus 72%, P = 0.001), and overall survival (OS) (57% versus 75%, P = 0.001) as compared to patients with PNI-negative disease. On multivariate analysis, PNI was significant factor only for OS ( P = 0.05), not for DFS ( P = 0.152) or LRC ( P = 0.174). For PNI-positive cohort, patients with perinodal extension had poor OS ( P = 0.01).

CONCLUSION

PNI-positive disease had poor outcomes despite aggressive multimodality treatment. PNI positivity correlated with higher pT stage, pN stage, overall stage and poor differentiation. PNI may be considered an independent prognostic factor for OS in oral cavity cancers and should be evaluated further in a randomized controlled setting. Added presence of perinodal extension defines poor outcomes. Sub-classification of PNI may be tested for determining impact on outcomes.