 Patients will receive a single administration of NBTXR3 on day 1, either as an intra-arterial or intratumor injection, followed by Intensity Modulated Radiation Therapy starting 24 hours later day 2, and up to completion of 7 weeks, i.e. 70 Grays, 2Graysfraction. Patients whose tumor has completely shrunk will be followed for the post-radiotherapy evaluation up to the End of Treatment visit. Those patients whose tumor has not shrunk more than 50 of the baseline size, will stop the radiotherapy and may have a salvage tumor surgery. Then, all patients will be followed every 8 weeks, for the safety evaluation and cancer disease status until the end of the study. 