Positron Emission Tomography-Based Response to Target and Immunotherapies in Oncology

Abstract

2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) is a promising tool to support the evaluation of response to either target therapies or immunotherapy with immune checkpoint inhibitors both in clinical trials and, in selected patients, at the single patient’s level. The present review aims to discuss available evidence related to the use of [18F]FDG PET (Positron Emission Tomography) to evaluate the response to target therapies and immune checkpoint inhibitors. Criteria proposed for the standardization of the definition of the PET-based response and complementary value with respect to morphological imaging are commented on. The use of PET-based assessment of the response through metabolic pathways other than glucose metabolism is also relevant in the framework of personalized cancer treatment. A brief discussion of the preliminary evidence for the use of non-FDG PET tracers in the evaluation of the response to new therapies is also provided.

The Role of the Immune Metabolic Prognostic Index in Patients with Non-Small Cell Lung Cancer (NSCLC) in Radiological Progression during Treatment with Nivolumab

“…Inflammatory infiltration and related tumor changes can also hamper the FDG PET/CTbased response's reliability. However, several studies have to date suggested a potential added value of this approach, at least in selected patients [24]. In a previous study by our group comparing the first response assessment to Nivolumab using CT and FDG PETbased criteria in the same cohort of patients, FDG imaging maintained a prognostic value even in patients classified as PD based on CT [28].…”

“…As the anticancer immune response results from the complex interplay between T cells and other immune cells, peripheral biomarkers increased attention even in the setting of immunotherapy [19][20][21][22]. On the other hand, 18F-fluorodeoxyglucose positron emission tomography (FDG PET/CT) can display the tumor microenvironment's glucose consumption [23][24][25]. Thus, it is reasonable to assume that the combination of FDG PET/CT with systemic inflammation indexes might further improve cancer patients' prognostic stratification.…”

NSCLC Biomarkers to Predict Response to Immunotherapy with Checkpoint Inhibitors (ICI): From the Cells to In Vivo Images

“…Compared with morphologic imaging, [18F]FDG PET/CT images can early detect irAEs due to the increased uptake of [18F]FDG at these sites. This potentially allows for a rapid intervention in life-threatening cases, such as severe colitis, pneumonitis, and pancreatitis [ 127 , 151 ].…”

Prediction of Response in Head and Neck Tumor: Focus on Main Hot Topics in Research

“…Finally, the emerging role of immunotherapy and in particular of immune checkpoints inhibitors (ICPIs) in several cancers, including HNC have further stimulated the development of PET-based prognostic biomarkers ( 66 ). RT can modify the expression of some receptor (as PD1/PD-L1) on cancer cells or on myeloid cells, which may affect response to PD-1-based immunotherapy.…”