A Study to Assess the Ability of Stereotactic Radiotherapy to Restore the Efficacy of Immunotherapy in Patients With Metastatic Cancer.

Inclusion criteria

• Male or female, 18 years of age or older,
• Patient with a metastatic solid tumor,
• Patient with at least one target lesion (for radiotherapy) together with other secondary lesions that must be measurable,
• Measurable disease according to RECIST 1.1 and iRECIST criteria,
• Patient undergoing anti-PD1 immunotherapy as part of standard of care treatment,
• Disease progression with immunotherapy (progression assessed by iRECIST criteria) but having received at least 6 months of immunotherapy,
• Performance Status (PS) of 0 or 1,
• Patient eligible for stereotactic radiotherapy,
• Patient affiliated to or benefiting from a social security scheme,
• Patient having been informed of the investigation and having signed the informed consent form prior to any study-specific procedures,
• Patient willing and able to undergo all examinations and procedures in accordance with the clinical investigation plan.

Exclusion criteria

• Patient having received previous radiotherapy since the start of immunotherapy,
• Patient for whom first disease progression (pre-inclusion stage) is not confirmed secondarily (inclusion stage),
• Patient with an active implantable medical device (e.g. pacemaker) or an active medical device worn on the body that could interact adversely with stereotactic radiotherapy treatment,
• Patient with hematological cancer,
• Symptomatic patient requiring a rapid change of systemic line according to the investigator's judgment,
• Concurrent participation in another clinical trial, or patient having received an investigational product within 30 days prior to inclusion,
• Pregnant or breast-feeding women,
• Patient under legal protection.