Phase 2 5-Day Preoperative Radiation for Soft Tissue Sarcoma

Inclusion Criteria: 1. Histologically confirmed soft tissue sarcoma of the extremity, trunk or retroperitoneum. 2. Has been offered preoperative radiation and surgery as part of standard-of-care treatment 3. Age ≥ 18 4. KPS ≥ 70 or ECOG 0 to 2 5. Life expectancy ≥ 6 months 6. If a woman is of childbearing potential, a negative serum or urine pregnancy test must be documented. 7. Ability to understand and the willingness to personally sign the written IRB approved informed consent document. Exclusion Criteria: 1. History of prior radiation to the area to be treated. 2. Active use of other anti-cancer investigational agents. 3. Planned use of concurrent chemotherapy, targeted therapy, or immunotherapy with radiation therapy (defined as the time interval starting 1 week before the first and last fraction of radiation therapy and surgery). 4. Pregnancy.