Would you consider preoperative radiation for a retroperitoneal sarcoma in a patient with Li Fraumeni syndrome where upfront surgery is likely to yield a positive margin?

This is a scenario where multi-disciplinary discussion is key. First, what is the histology of the RP sarcoma? Second, where is the likely positive margin, and do we expect potential downstaging with RT to impact this margin? Consideration for systemic therapy with restaging and consideration for RT...