Abstract
Objective Report routes of skull base invasion for head and neck nonmelanoma skin cancers (NMSCs)
and their survival outcomes.
Design Retrospective.
Participants Ninety patients with NMSC with skull base invasion between 2004 and 2014.
Major Outcome Measures Demographic, tumor characteristics, and treatments associated with different types
of skull base invasion and disease-specific survival (DSS) and overall survival (OS).
Results Perineural invasion (PNI) to the skull base occurred in 69% of patients, whereas
38% had direct skull base invasion. Age, histology, orbital invasion, active immunosuppression,
cranial nerve (CN) involved, and type of skull base invasion were significantly associated
with DSS and OS (p < 0.05). Patients with basal cell carcinoma (BCC) had significantly improved DSS
and OS compared with other histologies (p < 0.05). Patients with CN V PNI had significantly improved DSS and OS compared with
CN VII PNI (p < 0.05). Patients with zone II PNI had significantly improved DSS and OS compared
with those with direct invasion or zone III PNI (p < 0.05). Nonsurgical therapy was rarely used and is associated with a reduction in
DSS and OS (p < 0.05).
Conclusion Patterns and survival outcomes for NMSC skull base invasion are reported. Zone II
PNI, BCC, and CN V PNI are associated with improved survival outcomes.
Keywords
skin cancer - skull base invasion - direct invasion - intracranial invasion - risk
factors - survival outcomes - perineural spread