Patterns and Incidence of Neural Invasion in Patients With Cancers of the Paranasal Sinuses

Objective: To characterize the incidence and pattern of neural invasion (NI) in patients with cancers of the paranasal sinuses and anterior skull base. Design: Retrospective study. Setting: A tertiary referral cancer center. Patients: The study included 208 patients with cancer of the paranasal sinuses. Patients with brain invasion or neurogenic tumors were excluded. Main Outcome Measure: Analysis of clinical and pathologic data on patients with cancer of the paranasal sinuses. Results: Forty-one specimens (20%) had evidence of NI. Sinonasal undifferentiated, adenoid cystic, and squamous cell carcinoma had a high propensity for NI, whereas melanoma and sarcoma rarely invaded nerves. Intraneural invasion was found in 32% of these cases, and 34% invaded more than 1 cm distal to the tumor. Neural invasion was associated with a high rate of positive margins, maxillary origin, and previous surgical treatment (P<.04) but not with stage, orbital invasion, or dural invasion. Patients with NI were more likely to undergo adjuvant radiotherapy (P=.003), which significantly improved survival in patients with minor salivary gland carcinomas (P=.04). Multivariate analysis showed that pathologic evidence of NI was not an independent predictor of outcome. Conclusions: Paranasal carcinomas have high propensity for NI, whereas melanoma and sarcoma rarely invade nerves. Patterns of NI include both perineural and intraneural invasion. Neural invasion is associated with positive margins, maxillary origin, and previous surgery.