RATIONALE: Radiation therapy given before surgery of soft tissue sarcoma decreases the size of the tumor mass and the presence of malignant cells in its peripheral region. NBTXR3 and radiation therapy may kill more cancer cells and increase the tumor shrinkage rendering surgery more feasible or easier and achieve better local control of the tumor.

PURPOSE: This phase II/III is a prospective randomized, multi-center, open-label and active controlled two arms study in patients with locally advanced soft tissue sarcoma (STS) of the extremity and trunk wall. Patients will be randomized to receive either NBTXR3 as intratumor injection, activated by external beam radiation therapy or external beam radiation therapy alone, as preoperative treatment. Once the radiotherapy treatment is completed, tumor surgery will be performed in all patients.

Patients who will be allocated in arm A, will receive a single intratumor injection of NBTXR3 and will receive external beam radiotherapy starting 24hrs after the injection up to completion of 5 weeks, 5 days a week of treatment (50Gy, 2Gy/fraction). Then, all patients will undergo surgical resection of the tumor 5 weeks later and will be followed for wound healing and toxicity assessment. A visit of end of treatment will take place approximately 3-4 weeks after surgery. Patients will be followed for evaluation of their disease status and adverse event until the end of study.

Inclusion Criteria:

• Age: 18 years and older

• Locally Advanced Soft Tissue Sarcoma of the Extremity and Trunk Wall

• All grades

• Candidate to radiotherapy + surgery (ESMO guideline 2014) i.e. tumor must not have involvement of bone and / or vessel and or nerve :

  • Primary tumor or,
  • Relapsed tumor, localized out of previously irradiated area

• WHO performance score 0 to 2

• Adequate function of bone marrow

• Adequate renal function

• Adequate hepatic function

• Adequate pulmonary function

• All female patients of childbearing potential must have a negative serum/urinary pregnancy test

Exclusion Criteria:

• Absence of written Informed Consent duly signed and dated
• Patients with the following histological type: embryonal or alveolar rhabdomyosarcoma, Ewing's sarcoma, osteosarcoma or chondrosarcoma, Kaposi's sarcoma, primitive neuroectodermal tumor, angiosarcoma, aggressive fibromatosis or dermatofibrosarcoma protuberans
• Soft Tissue Sarcoma of the Trunk Wall localized in the abdominal region i.e. the region defined cranially by the xiphoid process of the sternum and the costal margins, and caudally by the line joining the anterior superior iliac spines, both limited by the perpendicular lines crossing both nipples
• Patient with a calculated tumor baseline volume > 3000 mL
• Metastatic disease (CT-scan / MRI verification) with life expectancy shorter than 6 months
• Previous radiation therapy in relapse site of soft tissue sarcoma (no radiation re-challenge is permitted)
• Concurrent treatment with any other anticancer therapy, including chemotherapy, immunotherapy, targeted therapy, gene therapy, or patients planning to receive these treatments during the study
• Absence of histologically or cytologically proven cancer at the first diagnosis
• Previous neoadjuvant chemotherapy treatment given as an upfront of the current treatment line
• Hemolytic anemia
• Autoimmune disease
• Complete initial work up earlier than 4 weeks prior to patient registration
• Patients unable to comply with scheduled visits, treatment plans, laboratory tests, and other study procedures
• Patients participating in another clinical investigation at the time of signature of the informed consent