Hypofractionated Radiotherapy for Soft Tissue Sarcomas

One of the main challenges in treating sarcomas with radiation is the toxicity to normal structures around the sarcoma. Early reports suggest Hypofractionated Radiotherapy will be safe and effective for treatment of soft tissue sarcomas. However, given the rarity of this disease, the diversity of histological sub-types, and the variety of locations where these can occur (anywhere in the body), more data is needed to provide understanding of the safety and efficacy of hypofractionated radiotherapy for treatment of this disease. The hypothesis is that by using hypofractionated radiotherapy, highly conformal high dose radiation can be delivered to soft tissue sarcomas, while respecting established normal tissue constraints and that local control rates will be greater than historical rates reported with conventional fractionation. Eligible participants with biopsy proven soft tissue sarcoma will be on study for up to 60 months.

Participants will be treated with 3-8 fractions, with the maximum prescribed dose to the Planning Tumor Volume (PTV) volume being 60 Gy delivered over a period of at most 8 weeks.

Hypofractionated radiation is delivered using highly conformal technique, allowing for a high dose of radiation to be delivered precisely.

The primary endpoint is 2-year local control, defined as the proportion of participants whose best response as determined per RECIST criteria using imaging is Complete Response (CR), Partial Response (PR), or Stable Disease (SD) out of all participants who have received at least one fraction. Local control will be reported with an exact 95% confidence interval (CI).

2-year local control rates will be reported separately for primary sites vs. metastatic sites with exact 95% CI.

5-year local control rates will be reported separately for primary sites vs. metastatic sites with exact 95% CI.

Progression free survival (PFS) defined with follow-up radiological assessment with PFS calculated from the point of start of hypofractionated radiotherapy to the point of recurrence or death. Participants without documented progression who are alive at last follow-up will be censored at the date of the last radiologic assessment. PFS will be estimated using the Kaplan-Meier method.

Overall survival (OS) defined from the point of start of hypofractionated radiotherapy to the time of death or last follow-up if alive. Participants who are alive at last follow-up will be censored. OS will be estimated using the Kaplan-Meier method.

Inclusion Criteria: Biopsy proven soft tissue sarcoma, either localized and inoperable/unresectable or metastatic, that is deemed by the treating physician to be targetable with hypofractionated radiotherapy. Participant refuses surgery or is aware that surgery is not recommended for them Karnofsky performance status > 60 Able to understand and sign an informed consent form Exclusion Criteria: Pregnant Chemotherapy or systemic anti-cancer treatment within the preceding two weeks Unable to undergo imaging or positioning necessary for radiotherapy planning Prior radiation therapy in the field that, at the discretion of the treating physician, prevents safe delivery of hypofractionated radiotherapy.