Sorry for your troubles. I had 5 recurrences and radiation 3x. Doing reirridstion depends on many factors, including the dose already given, the field of radiation the toxicity level of vital structures, the doctors experience, and other matters. Maybe look into High dose intraoperative radiation treatment aka HD-IORT or Brachytherapy, which go directly on or in the tumor, and protects vital structures, and IORT is a one dose treatment during surgery after removeing the tumors. Sime had cyberknife for recurrences. What CCC is your father being treated at. Good luck.