Carcinoma of the skin with perineural invasion

To evaluate the outcome and patterns of relapse in patients treated for skin carcinoma of the head and neck with either microscopic or clinical perineural invasion.

Radiotherapy alone or combined with surgery was used to treat 135 patients with microscopic or clinical evidence of perineural invasion of skin carcinoma. All patients had at least 2 years of follow-up.

The 5-year local control rates without salvage therapy were 87% with microscopic perineural invasion and 55% with clinical perineural invasion. Overall, 88% of the local failures occurred in patients with positive margins. Almost half of the recurrences in patients with microscopic perineural invasion were limited to the first-echelon regional nodes. However, only 1 of 11 patients with basal cell carcinoma with microscopic perineural invasion had a nodal failure. Ninety percent of recurrences in patients with clinical perineural invasion occurred at the primary site. Cranial nerve deficits rarely improved after successful treatment of the primary disease. Radiographic abnormalities remained stable 30% of the time when patients had clinical evidence of progressive disease.

Radiotherapy in patients with skin cancer with clinical perineural invasion should include treatment of the first-echelon regional lymphatics. The risk of regional node involvement is also relatively high for patients with squamous cell carcinoma with microscopic perineural invasion. In patients with clinical perineural invasion, the poor local control rates with conventional radiotherapy suggest a need for dose escalation with or without concomitant chemotherapy.