Predicting Radiotherapy Response and Toxicities in Soft Tissue Sarcoma of the Extremities - Cohort B

This is a multicentre prospective cohort study, primarily aimed at validating the dose-volume parameters identified in the analyses of the VorteX and IMRiS trials datasets.

• Delineation of healthy tissues

Pre-defined outlining guidelines of normal tissues as bones, muscle compartments, joints, lymph drainage basins and subcutaneous tissue from Predict A will be delineated in radiotherapy planning computed tomography (CT) images. All cases will be delineated by a single observer (Rita Simoes). Verification of all outlines will be carried out by Dr Aisha Miah (clinical supervisor).

• Dose-volume constraints validity testing

Patients will be treated as per local protocol treatment technique.

Radiotherapy, clinical and toxicities data will be collected, with no new intervention on the treatment. Patients enrolled will receive standard radiation prescription doses as described below:

• Pre-operative radiotherapy- 50 Gy in 25 fractions equivalent (pre-operative radiotherapy). Where appropriate hypo-fractionated schedules as per institutional guidelines can considered: eg. 25 Gy/ 5 daily fractions. In myxoid liposarcomas, 36 Gy in 18 fractions can be considered where suitable;
• Post-operative radiotherapy- 60 Gy in 30 fractions or 66 Gy in 33 fractions (positive resection margins); alternative hypo-fractionated schedules as per institutional guidelines can be considered;
• Palliative radiotherapy- 30-36 Gy in 10-12 daily fractions, 40-45 Gy in 15 fractions, 30-36 Gy in 5-6 once weekly fractions or 25 Gy in 5 daily fractions.

Toxicity will be assessed with the TESS and RTOG scoring instruments and Stern score for lymphoedema. Patients enrolled in the study will fill in a specific quality-of-life questionnaire to assess quality of life related functional outcomes following treatment for STSE. This questionnaire is based on validated questions for assessing quality-of-life. Patients will be followed up at 3, 6, 12, 18, and 24 months post-radiotherapy.

Inclusion criteria

• Histopathological diagnosis of soft tissue sarcoma of the upper or lower limb or limb girdle;
• Patients receiving pre-operative (neo-adjuvant), post-operative (adjuvant) or palliative radiotherapy;
• Patients receiving radiotherapy planned as per local protocols (neoadjuvant chemotherapy will be allowed). Neoadjuvant chemotherapy patients may be approached as they commence chemotherapy;
• WHO performance status 0-2;
• Aged ≥16 years;
• Patients fit enough to undergo radiotherapy treatment and willing to attend follow up visits, during two years;
• Female patients of child-bearing potential and male patients with partners of child-bearing potential must agree to use adequate contraception methods, which must be continued for 3 months after completion of treatment;
• Capable of giving written informed consent.

Exclusion criteria

• Previous radiotherapy to the same site;
• Pregnancy;
• Patients with concurrent or previous malignancy that could compromise assessment of primary and secondary endpoints of the trial.