When do you feel it is safe to initiate palliative radiation therapy to the bone (spine, femur, humerus, etc.) following surgical fixation with hardware (with or without cement) without compromising the stability of the hardware?  

It depends on the patient and clinical urgency to initiate radiation to bone following surgical fixation. Usually 2-4 weeks, 2 weeks is the earliest as long as patient’s pain is controlled post surgery and skin/incision is intact and healed. I usually start 3-4 weeks if radiation is not urgent...