A 53-year-old man treated for squamous cell carcinoma of the anus presents 4 weeks post-treatment with a 2-cm anal mass. What is the most appropriate next step in his management?
A 53-year-old man presents with a 4-cm anal tumor. The patient is diagnosed with squamous cell carcinoma of the anus (T3, N1, M0) and completes a course of chemoradiotherapy as definitive management. Four weeks post-treatment he presents to clinic for a follow-up visit. On physical examination, a rectal exam reveals a 2-cm exophytic anal mass.
What is the most appropriate next step in his management?