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.