18FDG PET for Early Identification of Tumor Exhaust for Immunotherapy in Patients With Locally Advanced or Metastatic Non-Small Cell Bronchopulmonary Carcinoma or Melanoma

The originality of this study is based on the stakes of the early prediction of resistance to immunotherapy (early therapeutic escapes, side effects, cost of treatment etc.). No prospective study has been published to date on the value of 18FDG PET to distinguish between true tumor progression and pseudo-progression. Studies are therefore needed to define new criteria for evaluating the metabolic response specific to immunotherapy, as well as the optimal timing of the interim examination. The goal is to conduct a transversal, non-randomized, prospective, multi-center, diagnostic performance study, harmonizing the moments of the 18FDG PET scans, acquisition conditions and interpretation criteria. The use of a dual-point acquisition in PET will also make it possible to judge the kinetics of 18FDG lesion capture (calculation of the 18FDG retention index on the late image) with the objective of highlighting PET criteria to distinguish between inflammatory pseudo-progression and true tumor progression in patients with unresectable melanoma or advanced or metastatic NSCLC. Other metabolic parameters will be studied, such as changes in tumor metabolic volume and binding intensities. Finally, this study will include patients to assess the correlation between the metabolic tumor response observed after 7 weeks of immunotherapy, the morphological response after 3 months of treatment (RECIST v1.1 and i-RECIST) and survival overall at 1 year.