This study is being done to examine whether proton therapy for certain kinds of sarcomas (extremity and trunk soft tissue) is safe and effective. As part of the study, patients will have five fractions of proton therapy before the participants have surgery for the sarcoma. The study will measure wound complications and functional outcomes / quality of life after the procedures. Patients will be asked to complete questionnaires about the treatment and quality of life from the time of enrollment until about two years after surgery. Otherwise, the participants will have standard of care follow ups with the treatment team.