This study compares carbon ion therapy, surgery, and proton therapy to determine if one has better disease control and fewer side effects. There are three types of radiation treatment used for pelvic bone sarcomas: surgery with or without photon/proton therapy, proton therapy alone, and carbon ion therapy alone. The purpose of this study is to compare quality of life among patients treated for pelvic bone sarcomas across the world, and to determine if carbon ion therapy improves quality of life compared to surgery and disease control compared with proton therapy.