PERINEURAL INVASION IN SQUAMOUS-CELL CARCINOMA OF THE HEAD AND NECK

Objective: To determine if perineural invasion (PNI) of small nerves a ffects the outcome of patients with squamous cell carcinoma (SCC) of t he upper aerodigestive tract. Design: Retrospective clinicopathologica l study of patients with at least 2 years of follow-up and with negati ve margins and no prior, synchronous, or metachronous SCC. Setting: Ac ademic otolaryngology department. Patients: One hundred forty-two pati ents who had SCC of the oral cavity, oropharynx and hypopharynx, or la rynx resected between 1981 and 1991. Intervention: Surgery with or wit hout adjuvant therapy. Main Outcome Measures: Local recurrence was exa mined with respect to PNI, nerve diameter, and microvascular or microl ymphatic invasion. Perineural invasion was correlated with lymph node metastasis, extracapsular spread, and survival. Results: :Perineural i nvasion of nerves less than 1 mm in diameter was present in 74 patient s, lymphatic invasion in 53, and vascular invasion in 9. Perineural in vasion was significantly associated with local recurrence (23% for PNI vs 9% for no PNI; P = .02), and disease-specific mortality (54% morta lity for PNI vs 25% for no PNI; P < .001). With extralaryngeal tumors, PNI was associated with nodal metastasis (73% vs 46%; P = .03). Perin eural invasion was not associated with extracapsular spread (P = .47). Microvascular invasion, lymphatic invasion, and nerve diameter were n ot significantly related to local recurrence. Conclusions: Perineural invasion of small nerves is associated with an increased risk of local recurrence and cervical metastasis and is, independent of extracapsul ar spread, a predictor of survival for patients with SCC of the upper aerodigestive tract.