Introduction Two mechanisms of action production of free radicals direct genetic damage Indications Indications of external beam irradiation definitive control (primary malignant bone tumors) Ewing sarcoma/primative neuroectodermal tumor primary lymphoma of bone hemangioendothelioma solitary plasmacytoma of bone adjuvant to surgical excision soft tissue sarcomas login to view 2 more bullets palliative care and impending fracture fixation metastatic bone disease login to view 4 more bullets Technique 1 rad = 1 centiGray Typical dose is 180-200 cGy/day radiation is given in "fractions" as radiotherapy is cumulative the total dose of therapy is the summation of all the separate fractions given during treatment Total dose < 45 Gray: usually leads to uncomplicated tissue healing 45 - 55 Gray: tissue usually heals but with problems > 60 Gray: tissue unlikely to heal Preoperative vs. Postoperative Preoperative vs. Postoperative Radiation Preoperative RT (neoadjuvant) Postoperative RT (adjuvant) Wound complications More wound complications (up to 40%) Less wound complications (<20%) Edema, fibrosis, joint stiffness Less (<15%) More edema, fibrosis, joint stiffness (>20%) (usually temporary) Radiation field Smaller field Larger field Pseudocapsule Allows formation of pseudocapsule to facilitate close-margin resection No pseudocapsule advantage Tumor shrinkage Helps shrink tumor prior to surgery No tumor shrinkage advantage Local recurrence Lower local recurrence rates Higher local recurrence rates Complications Soft tissue complications early effects delayed wound healing infection desquamation late effects fibrosis joint stiffness secondary sarcoma (below) fractures (below) Post-radiation sarcoma defined by the development of a sarcoma in a region previously radiated for malignancy incidence is ~13% more frequent in patients with prior chemotherapy overal patient prognosis is very poor Post-radiation fractures approximately 25% incidence following soft tissue sarcoma resection and external beam irradiation risk factors for post radiation fracture login to view 9 more bullets