Survival outcomes in locally advanced cutaneous squamous cell carcinoma presenting with clinical perineural invasion alone

Background: Cutaneous squamous cell carcinomas (CSCC) involving the head and neck are common, but initial presentation or recurrence limited to the cranial nerves is rare. Methods: We conducted a retrospective study of 21 patients with clinical perineural invasion (PNI) from CSCC and no measurable disease by RECIST 1.1. Patients treated with radiotherapy or chemoradiotherapy were included. Results: The median time from symptom onset until diagnosis was 13.0 months (2.6–83.1). All patients received radiotherapy. Fourteen received concurrent systemic therapy. The median follow-up time was 30.5 months (1.1–106.0). Ten patients recurred, with the majority being locoregional. The 2-year overall survival rate was 85%. The median progression-free survival (PFS) was 21.5 months with an estimated 2-year PFS of 44.5% (95%CI: 22.3–66.8). Conclusions: CSCCs with clinical PNI alone are difficult to diagnose and can have a long interval between appearance of symptoms and diagnosis. They can successfully be treated with chemoradiotherapy. However, many patients still suffer from locoregional recurrences.