Imaging Characteristics and Diagnostic Performance of 2-deoxy-2-[18F]fluoro-d-Glucose PET/CT for Melanoma Patients Who Demonstrate Hyperprogressive Disease When Treated with Immunotherapy

We investigated the ability of baseline 2-deoxy-2-[18F]fluoro-d-glucose PET/CT parameters, acquired before the start of immunotherapy, to predict development of hyperprogressive disease (HPD) in melanoma patients. We also evaluated the diagnostic performances of ratios of baseline and first restaging PET/CT parameters to diagnose HPD without information of the tumor growth kinetic ratio (TGKR) that requires pre-baseline imaging before baseline imaging (3 timepoint imaging). Seventy-six patients who underwent PET/CT before and approximately 3 months following initiation of immunotherapy were included. PET/CT parameters, including metabolic tumor volume (MTV) for all melanoma lesions and total measured tumor burden (TMTB) based on irRECIST, were measured from baseline PET/CT (MTVbase and TMTBbase) and first restaging PET/CT (MTVpost and TMTBpost). The ratios of MTV (MTVpost/MTVbase, MTVr) and TMTB (TMTBpost/TMTBbase, TMTBr) were calculated. MTVbase of HPD patients (n = 9, TGKR ≥ 2) was larger than that of non-HPD (n = 67, TGKR