A 68-year-old farmer from rural Maharashtra presents with a 3-month history of a non-healing ulcer on the dorsum of his left hand. On examination, there is a 2 cm × 1.5 cm ulcer with raised, indurated, everted edges and a granulating base. The lesion is painless. Dermoscopy shows keratin pearls and increased vascularity. A punch biopsy confirms well-differentiated squamous cell carcinoma (SCC) with no evidence of perineural invasion. There are no palpable regional lymph nodes. What is the most appropriate next step in management?