Skull Base Invasion Patterns and Survival Outcomes of Nonmelanoma Skin Cancers.

Report routes of skull base invasion for head and neck nonmelanoma skin cancers (NMSCs) and their survival outcomes.  Retrospective.  Ninety patients with NMSC with skull base invasion between 2004 and 2014.  Demographic, tumor characteristics, and treatments associated with different types of skull base invasion and disease-specific survival (DSS) and overall survival (OS).  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 ( < 0.05). Patients with basal cell carcinoma (BCC) had significantly improved DSS and OS compared with other histologies ( < 0.05). Patients with CN V PNI had significantly improved DSS and OS compared with CN VII PNI ( < 0.05). Patients with zone II PNI had significantly improved DSS and OS compared with those with direct invasion or zone III PNI ( < 0.05). Nonsurgical therapy was rarely used and is associated with a reduction in DSS and OS ( < 0.05).  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.