Prognostic Role of Pre-Treatment [(18)F]FDG PET/CT in Patients with Anaplastic Thyroid Cancer

SIMPLE SUMMARY: This study evaluates the prognostic capability of the (18)fluorodeoxyglucose ([(18)F]FDG) positron emission tomography (PET)/computed tomography (CT) in patients with anaplastic thyroid cancer (ATC) which can be used as a potential biomarker reflecting glycolysis. ATC is a rare, but highly lethal disease with a one-year overall survival of 20%, and its prognostic factors have rarely been investigated. In this study, survival data correlated with PET/CT derived parameters provide evidence that FDG uptake assessed by PET/CT is a prognostic marker, which may have a clinical impact on the management of patients with ATC. ABSTRACT: Anaplastic thyroid carcinoma (ATC) is a rare but highly lethal disease. Therefore, its diagnosis at an early stage and a rapid and accurate establishment of a proper treatment strategy is warranted. Tumor glycolysis assessed by (18)fluorodeoxyglucose ([(18)F]FDG) positron emission tomography (PET)/computed tomography (CT) is predictive of many cancers despite its limited proven applicability to ATC. We investigated the prognostic capability of [(18)F]FDG PET/CT in patients with ATC. Forty patients with ATC were subjected to [(18)F]FDG PET/CT for pre-treatment evaluation. The tumor size and stage, overall survival (OS), and PET parameters, including the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were analyzed. The 1-year OS rate was 17.5% with a mean life expectancy of 7.1 months. Distant metastasis was detected solely using PET/CT in 37.5% of cases. High SUVmax, MTV, and TLG were significantly associated with poor prognosis (p < 0.001, p = 0.002, and p < 0.001, respectively). A significant difference (p < 0.001) was observed in OS between patients with a high and low tumor SUVmax. Glucose metabolism assessed by [(18)F]FDG PET/CT was significantly associated with the OS of patients with ATC. PET-derived parameters such as SUVmax, MTV, and TLG are useful prognostic biomarkers for ATC.