High Dose Intensity Modulated Proton Radiation Treatment +/- Surgical Resection of Sarcomas of the Spine, Sacrum and Base of Skull

* Before beginning radiation therapy, the participants will have a radiation planning computed tomographic (CT) scan of the tumor site. This is considered standard of care and the doctor will use the images from this scan to plan the radiation treatment. * Participants may also receive surgery either before or after the study radiation treatment. This surgery is also considered standard of care and would be done regardless of being in the research study. * The IMPT technique for delivering radiation is for research purposes only. Radiation treatment to the affected tumor will be given daily, Monday through Friday. * The following procedures will be performed once a week during treatment: assessment of nerve, neuromuscular, motor and sensory function by clinical exam and toxicity assessment. * Participants will return for follow-up visits after completion of the radiation treatment at the following intervals: 6 weeks after completion of treatment, 6 months after treatment, every 6 months thereafter for 4 years, and then each year after for up to 15 years.