A 79-year-old man is evaluated for pain in the buttocks region. He was diagnosed with non-Hodgkin large B-cell lymphoma 6 months ago. Although his lymphoma has responded well to therapy and he is without evidence of active disease, he required hospitalization three times for chemotherapy-associated complications during his treatment course. He has been bedbound at home during his lymphoma treatment. He describes the pain as severe when sitting and has difficulty finding a comfortable position lying down as well. He has the least pain when standing, but he is unable to stand for very long. He has had no fever. Medical history is otherwise remarkable for hypertension, hyperlipidemia, type 2 diabetes mellitus, and advanced chronic kidney disease being treated with in-center hemodialysis. Medications are felodipine, insulin, calcium carbonate, calcitriol, and erythropoietin.
On physical examination, the patient is afebrile, blood pressure is 104/58 mm Hg, and pulse rate is 64/min supine. BMI is 18. Weight is 58 kg (128 lb), decreased from 77 kg (170 lb) 5 months ago. He appears cachectic with temporal wasting. Examination of his back shows no vertebral tenderness to palpation. There is wasting of the gluteal muscles. Examination of the sacrum reveals a shallow ulcer that is 5 cm in diameter with a hard black eschar covering the base. There is no wound drainage and no surrounding erythema.
Which of the following is the most appropriate management of this patient's lesion?