The Role of [.sup.18]F-FLT PET/CT in Assessing Early Response to Transarterial Radioembolization and Chemoembolization in Patients with Primary and Metastatic Liver Tumors/Primer ve Metastatik Karaciger Tumorlu Hastalarda Transarteriyel Radyoembolizasyon ve Kemoembolizasyona Erken Yaniti Degerlendirmede [.sup.18]F-FLT PET/BT'nin Rolu

Objectives: Metastases and primary malignancies are common in the liver. Local ablative applications such as transarterial chemoembolization (TACE), and transarterial radioembolization (TARE) provide minimally invasive and safe treatment in unresectable liver tumors. Early detection of response to treatment prevents unnecessary toxicity and cost in non-responder patients and provides an earlier use of other options that may be effective. This study aimed to identify the role of [.sup.18]F-fluorothymidine (FLT) positron emission tomography/computed tomography (PET/CT) in the assessment of early response to TACE and TARE treatments in patients with unresectable primary and metastatic liver tumors. Methods: This single-center study included 63 patients who underwent [.sup.18]F-FLT PET/CT for response evaluation after TACE and TARE. After excluding 20 patients whose data were missing 43 TARE-receiving patients were analyzed. The compatibility of change in semi-quantitative values obtained from the [.sup.18]F-FLT PET/CT images with the treatment responses detected in [.sup.18]F-fluorodeoxyglucose PET/CT, CT, and MR images and survival was evaluated. Results: There was no correlation between early metabolic, morphological response, and [.sup.18]F-FLT uptake pattern, and change in standardized uptake values (SUV) which were [DELTA][SUV.sub.max], [DELTA][SUV.sub.mean], [DELTA][SUV.sub.peak]., [DELTA][SUV.sub.mean], [DELTA][SUV.sub.peak] values. There was no significant correlation between [.sup.18]F-FLT uptake pattern, [DELTA][SUV.sub.max], [DELTA][SUV.sub.mean], [DELTA][SUV.sub.peak], and overall survival, progression-free survival (PFS) for the target lobe PFS for the whole-body. The survival distributions for the patients with >30% change in [DELTA][SUV.sub.max] and [DELTA][SUV.sub.peak] values were statistically significantly longer than the patients with