Proton Chemoradiotherapy for High-Risk Soft Tissue Sarcomas

Inclusion Criteria: * Patients must have histologic and radiographic proof of localized high-risk soft tissue sarcoma (STS) required prior to registration. * For the purpose of this study, high risk STS is defined by at least two of the following risk factors: * Tumor ≥ 5 cm in maximal diameter on MRI or CT * Histology grade 3 or 4 (AJCC, 7th edition) * Tumor deep to the investing fascia * Locally recurrent sarcoma with no prior radiation therapy to the primary site * Age \>55 years old * Tumor must be considered potentially resectable as defined by cross sectional imaging. * At least 2 weeks must have elapsed from any prior surgery or hormonal therapy. Patients must have ≤ grade 1 acute toxicities of any prior treatment with anti-cancer modalities (returned to baseline status as noted before most recent treatment). Patients with persisting, stable chronic toxicities from prior treatment ≤ grade 1 are eligible. * Age ≥18 years at time of consent. * Physician documented life expectancy of greater than 3 months. * Patients must have normal organ and marrow function within 4 weeks prior to study treatment as defined below: * hemoglobin ≥ 9 g/dL * leukocytes ≥3,000/microliter (mcL) * absolute neutrophil count ≥1,500/mcL * platelets ≥100,000/mcL * total bilirubin ≤ institutional upper limit of normal * aspartate aminotransferase (AST/SGOT) and alanine aminotransferase(ALT/SGPT) \< 2.5 x institutional upper limit of normal * creatinine within 1.5 x upper limit of normal(ULN) * Women of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation and for 12 months after treatment. Patients must have a negative serum pregnancy test within 14 days prior to beginning treatment on this trial. Sexually active men must also use appropriate contraception method and should not father a child while receiving therapy during this study. * Ability to understand and the willingness to sign a written Institutional Review Board(IRB) stamped, study specific informed consent document prior to any research related procedures or study treatment. Exclusion Criteria: * Receiving any investigational agents. * Treatment with cytotoxic agents and/or treatment with biologic agents within the 4 weeks prior to beginning treatment on this study. * Evidence of metastatic disease. * Previous radiotherapy to the affected site. * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, uncontrolled cardiac arrhythmia, and/or psychiatric illness/social situations that would limit compliance with study requirements. * Pregnant women are excluded from this study because the investigational agents may have the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with these agents, breastfeeding should be discontinued if the mother is treated. * HIV-positive patients are ineligible because these patients are at increased risk of lethal infections when treated with marrow-suppressive therapy and the potential pharmacokinetic interaction between antiretroviral therapy and the investigational agents. * All herbal and/or alternative medications should be discontinued while on study, these include but are not limited to: Hydrastis canadensis (goldenseal), Uncaria tomentosa (cat's claw) or Echinacea angustifolia. * Requirement for treatment with immunosuppressive agents or chronic steroids. * A history of a hypersensitivity reaction to any of temozolomide's components or to Dacarbazine(DTIC).