Would you offer definitive radiation therapy for a Merkel cell carcinoma in which surgical resection would be disfiguring or result in significant dysfunction?

I would, but after an appropriate discussion. First, I favor full staging of all Merkel cell patients with a PET/CT (though many would argue this is not mandatory for small tumor, node-negative patients). I would also recommend a sentinel node procedure because the risk of nodal disease is significant even in small primary tumors. This is not a disfiguring procedure, and generally has a major impact on the treatment plan and prognosis.

For a patient who wishes to defer surgery, my opinion is that there is still no evidence to suggest that definitive radiation is equivalent to resection in terms of cancer outcomes for patients with macroscopic disease. Local control with radiation is quite good, 75-80% or higher, but I think likely slightly...