Would you recommend adjuvant radiation therapy to the locoregional lymph node basins for Merkel cell carcinoma (MCC) s/p WLE with negative margins and isolated tumor cells in 1 of 3 right inguinal sentinel lymph nodes?

Yes, this is not an easy disease to cure in the node-positive setting. So, the question can be framed: do isolated tumor cells constitute a benign finding, frank malignancy, or a space in between? I don't have an answer to that, and perhaps given the rarity of the entity, that answer will remain rec...