Objective: In recent years, the introduction of immune checkpoint inhibitors has significantly
changed the outcome of patients affected by lung cancer and cutaneous melanoma. Although the
clinical advantages, the selection of patients and the evaluation of response to immunotherapy remain
unclear, the immune-related Response Evaluation Criteria in Solid Tumor (irRECIST) was proposed as
an update of the RECIST criteria for the assessment of response to immunotherapy. However, morphological
images cannot predict early response to therapy that represents a challenge in clinical practice.
18F-FDG PET/CT before and after immunotherapy has an indeterminate role, demonstrating ambiguous
results due to inflammatory effects secondary to activation of the immune system. The aim of the
present review was to analyze the role of PET/CT as a guide for immunotherapy, by analyzing the
current status and future perspectives.
Methods: A literature search was conducted in order to select all papers that discussed the role of
PET/CT with FDG or other tracers in the evaluation or prediction of response to immunotherapy in
lung cancer patients.
Results: Many papers are now available. Many clinical trials have demonstrated the efficacy of immunotherapy
in lung cancer patients. FDG PET/CT can be used for the prediction of response to immunotherapy,
while its utility for the evaluation of response is not still clearly reported. Moreover, the standardization
of FDG PET/CT interpretation is missing and different criteria, such as information, have
been investigated until now.
Conclusions: The utility of FDG PET/CT for patients with lung cancer undergoing immunotherapies is
still preliminary and not well addressed. New agents for PET are promising, but large clinical trials are