Preoperative vs Postoperative IMRT for Extremity/Truncal STS

Perioperative RT in addition to surgery is widely accepted as standard management for soft tissue sarcoma (STS) of the extremity and trunk. However, controversy remains as to whether RT should be delivered preoperatively or postoperatively. While both confer similar rates of local control, preoperative RT leads to a decrease in late tissue morbidities such as fibrosis, limb edema, joint stiffness and fracture as compared to postoperative RT. The reasons for this are likely multifactorial, but are in part related to total dose delivered (50 Gray (GY) preoperatively and 60-66 Gy postoperatively) and, based on a previous National Cancer Institute (Canada) Phase III randomized controlled trial, the much larger volume treated in the postoperative setting compared to that in the preoperative setting. The optimal radiation dose used in the postoperative setting is unknown but has been developed empirically and doses of 60-66 Gy are generally employed.However, investigators in Norway/Sweden and France have found equivalent local control rates for patients with negative surgical margins treated with 50 GY postoperativelyThe main concern with preoperative RT has centered on the risk of an increased rate of delayed wound healing and major wound complications. Although some studies suggest it may be possible to reduce the incidence of acute wound healing complications associated with pre-operative radiation than previously seen in the 2D RT era, this has yet to be tested in the phase III setting. IG-IMRT allows a much higher degree of conformality and accurate delivery of dose to the tumour while sparing surrounding normal tissue. This may allow similar rates of acute wound healing complications for pre- and postoperative RT in the treatment of STS.

Inclusion criteria

• Histologically proven soft tissue sarcoma of the extremity or trunk following review by local reference pathologist.
• Deemed appropriate for preoperative or postoperative radiotherapy and conservative surgery following patient assessment by a radiation oncologist and surgical oncologist.
• Lesion is primary or locally recurrent. Patient may have undergone excisional biopsy with positive margins at a referring hospital and are eligible following discussion among the surgical oncologists and radiation oncologists that IMRT is an acceptable treatment for that case.
• Eastern Cooperative Oncology Group (ECOG) score 0-3
• Patient is aged 18years or older.
• Patient is able to provide informed consent
• Patient is available for treatment and follow-up.

Exclusion criteria

• Benign histology.
• Prior malignancy within the previous five years or concurrent malignancy with the exception of adequately treated basal cell carcinoma of the skin or carcinoma in-situ of the cervix.
• Prior radiotherapy to the target site
• Planned chemotherapy for (neo)adjuvant treatment
• Conservative surgery to the target site
• Presence of regional nodal disease or unequivocal distant metastases.
• Other major medical illness deemed to preclude safe administration of protocol treatment or required follow-up.