Pre-operative RadiothErapy for Soft Tissue SarcOmas

Soft tissue sarcomas (STSs) are malignant tumours that arise in any of the mesodermal tissues in the body including muscles, fibrous tissues, bone and cartilage, adipose tissue, and blood vessels, most frequently in the extremities (40%), trunk and retroperitoneum (40%).

Traditionally, the prescription schedule for conventional preoperative RT is a regimen of 50 Gy in fractions of 1.8-2 Gy per day. Concerns regarding this regimen include the delay to definitive surgery and the higher rate of wound complications compared to post-operative radiotherapy. Hypofractionated RT is a prescription schedule in which the total dose of radiation is delivered in larger doses per fraction in fewer fractions allowing the delivery of a higher biologically effective dose (BED) to the tumour than with conventional RT \[7\] during a shorter period of time.

This will be a phase I/II study of hypofractionation delivering five fractions (one fraction delivered every 2nd day) of 7 Gy of external beam radiotherapy over 5 fractions (one and half week period) in patients with localized STSs who are planned to receive pre-operative radiotherapy. Patients will undergo surgery 4-6 weeks after completion of RT.

Pre-treatment evaluation will be according to standard practice:

History and Physical Exam

* height,
* weight
* history (diabetes, vascular disease)

Radiology

* MRI of primary site or
* CT if MRI not tolerated
* CT chest

Quality of Life

* Musculoskeletal Tumour Society Rating Scale
* Toronto Extremity Salvage Score (TESS)

Follow-up assessment will be done as follows:

History and Physical Exam

* Acute radiation toxicity
* During RT and 2 weeks after end of RT

Acute surgical toxicity - wound assessment

* At hospital discharge,
* 2 weeks post-surgery
* 1 month post-surgery
* 3 months post-surgery
* 6 months post-surgery

Late toxicity (skin, subcutaneous, bone, joint) \& peripheral limb edema

- Every 6 months thereafter

Radiology

* Chest CT-scan
* Within 1 month pre-surgery
* Standard thereafter

MRI or CT scan of primary site

* Prior to surgery, as standard
* Every 3-6 months or as needed after surgery

Quality of life Questionnaires

* Toronto Extremity Salvage Score (TESS
* Musclo Tumor Rating Scale (MSTS)
* At months 1,3,6, 12, 18 and 24 after surgery.
* Yearly thereafter up to 5 years

Eligibility Criteria:
Inclusion Criteria:

* Histologically proven STS of the extremities, above the knee, or trunk following review by our pathologist

  * Lesions smaller than 15cm in largest dimension
  * Deemed appropriate for preoperative radiotherapy and conservative surgery following patient assessment by a radiation oncologist and surgical oncologist
  * Lesion is primary or locally recurrent. Patients who underwent unplanned non-oncological excision ("whoops" procedure) at a referring hospital are NOT eligible
  * No previous radiation therapy
  * ECOG 0-2 (or Karnofsky Performance Status ≥ 70) within 60 days prior to registration
  * Resectable primary lesion with or without distant metastasis
  * Age ≥ 18
  * Patient must be able to provide study-specific informed consent prior to study entry
  * Patient is available for treatment and follow-up

Exclusion Criteria:

* Patients who underwent unplanned non-oncological excision ("whoops" procedure) at a referring hospital

  * Lesions below the knee
  * Prior or concurrent invasive malignancy (except non-melanomatous skin cancer) or lymphomatous/hematogenous malignancy, unless continually disease free for a minimum of 5 years
  * Regional lymph node involvement
  * Previous irradiation to the area to be treated
  * Other major medical illness deemed to preclude safe administration of protocol treatment or required follow-up