A 72-year-old woman presents with a scaly, indurated nodule on the left temple that has grown over 6 months. She has a history of actinic keratosis in the same area. Dermoscopy reveals a hyperkeratotic plug with irregular vascular pattern. Excisional biopsy shows moderately differentiated squamous cell carcinoma with invasion into the subcutaneous fat and perineural invasion. The margins are clear (>5 mm). What is the most appropriate next step in management?