What is an appropriate target volume for a chordoma or chondrosarcoma after a gross total resection?

The CTV for postop chordoma or chondrosarcoma after gross total resection should include the entire surgical resection cavity as well as incision and drain sites with a 1 cm margin for the initial 50.4 Gy. Then cone down off the incision and drain site and cover the high risk margins based on the or...