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.