Risks and clinical implications of perineural invasion in T1-2 oral tongue squamous cell carcinoma.

BACKGROUND Risks of perineural invasion (PNI) in T1-2 oral tongue squamous cell carcinoma (SCC) have not been specifically elucidated. METHODS Pathological features, including PNI, were re-reviewed under regular hematoxylin-eosin staining in 190 patients with T1-2 oral tongue SCC. RESULTS Tumor thickness >5 mm, PNI(+), and lymphovascular invasion (+) independently predicted lymph node involvement. PNI(+) and neck observation also independently predicted neck recurrence, but only PNI(+) was associated with a poor disease-specific survival (DSS; p = .003). In patients who were clinically node negative (cN0), elective neck dissection contributed to a better DSS in patients with PNI(+) tumors (p = .046), but not in patients with PNI (-) tumors (p = .809). Additionally, increased tumor thickness predicted the presence of PNI. CONCLUSION PNI is a crucial pathological feature for T1-2 oral tongue SCC. Elective neck dissection should be performed in patients who were cN0 with PNI. Careful evaluation for PNI should be advocated in regular pathological diagnosis.