FDG PET/CT Radiomics Analyses of Lung Cancer Patients Treated With Immunotherapy

The investigators hypothesise that molecular imaging-based RADIOMICS analysis of FDG PET/CT data (termed iRADIOMICS) provides more information than standard anatomical imaging-based irRC analysis regarding the assessment of the effectiveness of immunotherapy and will have a stronger predictive power. It is widely accepted that molecular imaging (e.g. PET/CT) reflects changes in tissues much sooner than anatomical imaging (CT, MRI). Therefore, the investigators expect that an immunotherapy assessment tool based on FDG PET/CT should outperform anatomical-imaging-based irRC also timewise. Although the investigators do expect an initial increase in FDG PET uptake (mainly due to the metabolic activity of tumour infiltrating lymphocytes (TILs)), followed by a late decrease, the investigators argue that the predictive power of FDG PET can be even further increased by including an in-depth analysis of additional imaging features - the aforementioned "radiomics texture features". Many studies across different types of cancer have found a correlation between the presence of TILs and patient survival. Therefore the investigators expect that iRADIOMICS signature of responders will be different from the irRADIOMICS signature of non-responders to antiPD1 immunotherapy due to the different levels of TILs infiltration, different TILs spatial distribution within the tumour, and different composition of immunosuppressive tumour microenvironment containing different levels and spatial distribution of various immunosuppressive cells, such as myeloid-derived suppressive cells (MDSC), regulatory T cells (Treg), tumour-associated macrophages (TAM), regulatory dendritic cells (DCreg) and others 30. Thus the investigators anticipate that it might be possible to assess the response to immunotherapy at just one imaging time-point, preferably already in the pseudo-progression phase, thus much earlier than with irRC. Based on the assumption that irRADIOMICS might be able to detect differences in tumour immunosuppressive microenvironment, the investiagators further hypothesise that it might be also possible to predict, which patients are most likely to benefit from anti-PD1 immunotherapy already before the therapy.