Investigational procedure
lymphopenia, Tumor
LYMPHOPENIA, TUMOR
Each lesion will be treated with SBRT using 3 fractions of 8 Gy prescribed on the PTV (Planned Tumor Volume), with one fraction delivered every day, ideally Monday, Wednesday, and Friday, so the treatment period will therefore be five days. For technical reasons (breakdown, maintenance, etc.), two fractions will be delivered over two successive days, with a minimum delay of 24 hours between two fractions. A total treatment period of 5 days will be accepted.Treatment must be delivered by a regular LINAC (Linear Accelerator) or MRI (Magnetic resonance Imaging) machine using the SBRT technique to all lesions and isocenters. Daily IGRT (Image-Guided Radiation Therapy) is required. If it’s possible, we encourage avoiding the VMAT (Volumetric Modulated Arc Therapy) technique to decrease the risk of lymphopenia, which may be associated with anti-tumoral immunity reduction. For this SBRT prescription condition, at least 95% of PTV will have to receive 100% of the prescribed dose (24 Gy).Patients included in this study will present at least three lesions. In order to guide which lesions to irradiate, the following principles should be used:
To irradiate at least two measurable lesionsTo let at least one measurable non-irradiated lesion to evaluate the abscopal effect. Of note, this non-irradiated lesion can be the one biopsied.To try to irradiate the majority of the lesions, however, it is mandatory to respect the constraints on OARs (organs at risk).Dose constraints for OARs are defined in Table 
Dose contraints to OARs