A 58-year-old man presents for evaluation of a changing mole on his upper back. He reports that over the past 4 months it has enlarged and become darker, and it occasionally itches. He has a history of blistering sunburns as a teenager and has >50 nevi. Physical examination shows a 1.1-cm asymmetric, irregularly bordered, variegated brown-black macule with a small area of erythema. Dermoscopy is concerning for melanoma. A punch biopsy confirms malignant melanoma. Which of the following is the most appropriate next step in management of this lesion?

(Assume no evidence of distant metastasis on initial evaluation.)