High Precision RT For Soft-Tissue Sarcoma

Phase 2

Completed

Interventions: Radiation: Intensity-Modulated Radiotherapy
Radiation: Daily Cone Beam CT

Brief Summary: This research study aims at defining 1) how retroperitoneal sarcomas change over the course of radiotherapy and 2) how radiotherapy affects your well-being. While the investigators know that radiotherapy before surgery is safe and effective, the amount of tumor motion and size change during radiotherapy is unknown. There is also very little information that describes the side-effects of radiotherapy in the treatment of this disease.

Detailed Description: Soft-tissue sarcomas (STS) that arise from the retroperitoneum are rare malignancies that are anatomical located deep within the abdominal area and thus pose challenges to surgical and radiotherapeutic management of the patient. As a result, the local control and overall survival for patients with retroperitoneal sarcomas (RPS) are worse than STS from the extremities. Current treatment strategy involves pre-operative radiotherapy followed by surgery. Use of intensity-modulated radiotherapy (IMRT) in RPS had allowed for more conformal treatments with the aim of sparing normal tissues from high doses of irradiation. Yet the accuracy and coverage of IMRT depend highly on target motion, and little is known about the motion of RPS during the course of radiotherapy. As well, RPS are commonly in close proximity to sensitive organs for which the long-term toxicity and effect on quality of life secondary to radiation is unknown. The current study seeks to evaluate the extent of tumor motion during radiotherapy and the impact of radiotherapy to patient toxicity and quality of life. At the conclusion of this study, our results will hopefully identify the optimum PTV, the importance of different normal tissues and their dose-volume constraints, the role of image guidance, and the potential for dose escalation in the treatment of RPS.

Recruitment & Eligibility

Inclusion Criteria

Pathologically (histologically or cytologically) proven diagnosis of sarcoma (except for GIST, Ewing's sarcoma and rhabdomyosarcoma) within the retroperitoneum. These include patients with locally recurrent disease
Planned to receive pre-operative radiotherapy
Will undergo a planning CT
Karnofsky Performance Status of ≥ 70 within 28 days prior to study entry
No systemic chemotherapy given prior to pre-operative radiotherapy
Able to provide written, informed consent
Women of childbearing potential and men who are sexually active must practice adequate contraception.

Exclusion Criteria

Tumor pathology of GIST, Ewing's sarcoma or rhabdomyosarcoma
Metastatic disease to the retroperitoneum from a primary sarcoma not originating from the retroperitoneum
Systemic chemotherapy given prior to pre-operative radiotherapy.
Intent on giving chemotherapy ≤ 12 months from the completion of radiotherapy
Inability to undergo a 4D-CT simulation
KPS < 70
Unable to provide informed consent
Pregnant women

Arm && Interventions

Group	Intervention	Description
Prospective	Intensity-Modulated Radiotherapy	-
Prospective	Daily Cone Beam CT	-

Primary Outcome Measures

Name	Time	Method
To determine the extent of inter-fractional and intra-fractional movement of the GTV during radiotherapy treatments.	3 years	To quantify and describe the movement of the tumor during and between radiotherapy treatments using imagings acquired during the course of radiotherapy planning and treatments.
To assess the acute and long-term toxicity of pre-operative radiotherapy as a function of the dose given to normal tissues and its impact on patient quality of life.	10 years	To describe the effect of radiotherapy to the patient by measuring the acute and long-term side-effects of radiation therapy.

Secondary Outcome Measures

Name	Time	Method
Describe variations in the volume and shape of the GTV over the course of the treatment and need for adaptive therapy.	3 years	To measure and better define the response of the tumor to radiotherapy during treatments.
Correlate the pattern of local recurrence with the dose of radiation delivered accounting for motions and volume changes of target structures.	10 years	To determine whether there is a pattern of local relapse with the actual dose of radiation delivered to the tumor environment when tumor volumetric and positional changes are taken into account.