Would you offer adjuvant radiation therapy for a Merkel cell carcinoma limited to the epidermis with close margins?

I would review this case with a dermatopathology expert before making any decisions. The reason is that normal Merkel cells usually lie in very close proximity to the basement membrane. My understanding is that a skin neoplasm that is limited to the epidermis does not broach the basement membrane, and is, therefore, an "in situ" neoplasm, rather than a bona fide "carcinoma." In a case like this, a re-excision of the area might be a valuable diagnostic (and potentially therapeutic) maneuver and help clarify whether this is actually an invasive carcinoma or not, which would be important to know when predicting natural history and devising an appropriate management plan.