Interim FDG PET-CT in Melanoma Metastatic Patient's Treated by Anti-PD1 Therapy

Who May Qualify: - Age greater than or equal to 18 years, - Patient with advanced melanoma proved histologically, not BRAF mutated, BRAFV600 mutated and wild mutated, cutaneous or unknown primary melanoma having an indication of treatment with anti-PD-1 immunotherapy by nivolumab or Pembrolizumab, - Patient having social insurance, - Patient who has signed willing to sign a consent form. Who Should NOT Join This Trial: - Age less than 18 years, - Patient with ocular or mucosal melanoma, - Contraindication to PET CT examination: Severe claustrophobia, unbalanced diabetes (fasting hairy blood glucose ≥ 11 mmol), - Patient with only metastatic lesions less than 8 mm in size, with the exception of pulmonary nodules, - HIV and/or HCV (hepatitis C virus) and/or HBV (hepatitis B virus) positive serology, active autoimmune conditions (where your immune system attacks your own body), - Withdrawal of willing to sign a consent form, - Metastatic disease not confirmed histologically. Always talk to your doctor about whether this trial is right for you.