For any microscope cancer that was left behind, which also can go to the flap, flaps also protects vital structures, areas radiated before, so can take the toxicity. The reirridation may be 45Gy, not really sure in this case, but is not usually like 70Gy. IORT is equivalent to 3-4 times the amount in IMRT, and dosages are between 10-20Gy, but is really triple that. Good luck.