18F-choline PET-computed tomography for the prediction of early treatment responses to transarterial radioembolization in patients with hepatocellular carcinoma

PET/CT with 18F-choline or 18F-FDG in Hepatocellular Carcinoma Submitted to 90Y-TARE: A Real-World Study

Our aim was to assess the role of positron emission computed tomography (PET/CT) with 18F-choline (18F-FCH) or 18F-fluorodeoxyglucose (18F-FDG) in hepatocellular carcinoma (HCC) submitted to 90Y-radioembolization (90Y-TARE). We retrospectively analyzed clinical records of 21 HCC patients submitted to PET/CT with 18F-fluorocholine (18F-FCH) or 18F-fluodeoxyglucose (18F-FDG) before and 8 weeks after 90Y-TARE. On pre-treatment PET/CT, 13 subjects (61.9%) were 18F-FCH-positive, while 8 (38.1%) resulted 18F-FCH-negative and 18F-FDG-positive. At 8-weeks post 90Y-TARE PET/CT, 13 subjects showed partial metabolic response and 8 resulted non-responders, with a higher response rate among 18F-FCH-positive with respect to 18F-FDG-positive patients (i.e., 76.9% vs. 37.5%, p = 0.46). Post-treatment PET/CT influenced patients’ clinical management in 10 cases (47.6%); in 8 subjects it provided indication for a second 90Y-TARE targeting metabolically active HCC remnant, while in 2 patients it led to a PET-guided radiotherapy on metastatic nodes. By Kaplan−Meier analysis, patients’ age (≤69 y) and post 90Y-TARE PET/CT’s impact on clinical management significantly correlated with overall survival (OS). In Cox multivariate analysis, PET/CT’s impact on clinical management remained the only predictor of patients’ OS (p < 0.001). In our real-world study, PET/CT with 18F-FCH or 18F-FDG influenced clinical management and affected the final outcome for HCC patients treated with 90Y-TARE.

Local-Regional Treatment of Hepatocellular Carcinoma: A Primer for Radiologists

The treatment planning for patients with hepatocellular carcinoma (HCC) relies predominantly on tumor burden, clinical performance, and liver function test results. Curative treatments such as resection, liver transplantation, and ablative therapies of small lesions should be considered for all patients with HCC. However, many patients are ineligible for these treatments owing to advanced disease stage and comorbidities. Despite efforts to increase screening, early-stage HCC remains difficult to diagnose, which decreases the possibility of curative therapies. In this context, local-regional treatment of HCC is accepted as a form of curative therapy in selected patients with early-stage disease, as a therapeutic option in patients who are not eligible to undergo curative therapies, as a downstaging approach to decrease tumor size toward meeting the criteria for liver transplantation, and as a bridging therapy to avoid tumor growth while the patient is on the waiting list for liver transplantation. The authors review the indications, types, mechanism of action, and possible complications of local-regional treatment, as well as the expected postprocedural imaging features of HCC. Furthermore, they discuss the role of imaging in pre- and postprocedural settings, provide guidance on how to assess treatment response, and review the current limitations of imaging assessment. Finally, the authors summarize the potential future directions with imaging tools that may add value to contemporary practice at response assessment and imaging biomarkers for patient selection, treatment response, and prognosis. ©RSNA, 2022.

Radioembolization, Principles and indications

Radioembolization is the selective application of radionuclide-loaded microspheres into liver arteries for the therapy of liver tumours and metastases. In this review, we focused on therapy planning and dosimetry, as well as the main indications of 90Y-glass and resin microspheres and 166Ho-microspheres.