Background:
Immune checkpoint inhibitors (ICI) have achieved astonishing results and
improved overall survival (OS) in several types of malignancies, including advanced melanoma. However,
due to a peculiar type of anti-cancer activity provided by these drugs, the response patterns during
ICI treatment are completely different from that with “old” chemotherapeutic agents.
Objective:
To provide an overview of the available literature and potentials of 18F-FDG PET/CT in
advanced melanoma during the course of therapy with ICI in the context of treatment response
evaluation.
Methods:
Morphologic criteria, expressed by Response Evaluation Criteria in Solid Tumors (RECIST),
immune-related response criteria (irRC), irRECIST, and, more recently, immune-RECIST (iRECIST),
along with response criteria based on the metabolic parameters with 18F-Fluorodeoxyglucose (18FFDG),
have been explored.
Results:
To overcome the limits of traditional response criteria, new metabolic response criteria have
been introduced on time and are being continuously updated, such as the PET/CT Criteria for the early
prediction of Response to Immune checkpoint inhibitor Therapy (PECRIT), the PET Response Evaluation
Criteria for Immunotherapy (PERCIMT), and “immunotherapy-modified” PET Response Criteria
in Solid Tumors (imPERCIST). The introduction of new PET radiotracers, based on monoclonal antibodies
combined with radioactive elements (“immune-PET”), are of great interest.
Conclusion:
Although the role of 18F-FDG PET/CT in malignant melanoma has been widely validated
for detecting distant metastases and recurrences, evidences in course of ICI are still scarce and larger
multicenter clinical trials are needed.
993P Glycolytic tumor burden on pretreatment 18F-FDG PET/CT correlates with response and survival in metastatic NSCLC undergoing immune checkpoint inhibitors