Evaluating Treatment Response of Radioembolization in Intermediate-Stage Hepatocellular Carcinoma Patients Using 18F-Fluoroethylcholine PET/CT

Micro-Nano Convergence-Driven Radiotheranostic Revolution in Hepatocellular Carcinoma

Radiotherapy, as an important means of treating hepatocellular carcinoma (HCC), has shown unique therapeutic advantages, especially in patients who are unable to undergo surgery or transplantation. It mainly includes external radiotherapy, transarterial radioembolization and intratumoral radioactive particle implantation. However, under the influence of factors such as the hypoxic characteristics of the liver tumor microenvironment and the radioresistance of tumor cells, the effect of radiotherapy may be unstable and may cause side effects, affecting the quality of life of patients. In recent years, with the development of nanotechnology, drug delivery systems based on micro-nanomaterials have provided new solutions for improving the effect of radiotherapy for HCC. Despite this, the application of micro-nano drug delivery systems in the treatment of HCC still faces some challenges, mainly including the in vivo safety and in vivo metabolism of micro-nano materials. This article reviews the latest progress of micro-nano materials in the treatment of HCC, especially their application in radiosensitization and their clinical translation potential. This article systematically analyzes the role of micro-nanomaterials in external or internal radiotherapy sensitization and radioimmunotherapy and explores the advantages of micro-nanomaterials in improving the treatment effect of HCC.

Prognostic factors influencing outcomes in hepatocellular carcinoma patients undergoing selective internal radiation therapy

Selective internal radiation therapy (SIRT) has emerged as a viable endovascular treatment strategy for hepatocellular carcinoma (HCC). According to the Barcelona Clinic Liver Cancer (BCLC) classification, SIRT is currently recommended for early- and intermediate-stage HCC that is unsuitable for alternative locoregional therapies. Additionally, SIRT remains a recommended treatment for patients with advanced-stage HCC and portal vein thrombosis (PVT) without extrahepatic metastasis. Several studies have shown that SIRT is a versatile and promising treatment with a wide range of applications. Consequently, given its favourable characteristics in various scenarios, SIRT could be an encouraging treatment option for patients with HCC across different BCLC stages. Over the past decade, an increasing number of studies have focused on better understanding the prognostic factors associated with SIRT to identify patients who derive the most benefit from this treatment or to refine the optimal technical procedures of SIRT. Several variables can influence treatment decisions, with a growing emphasis on a personalised approach. This review, based on the literature, will focus on the prognostic factors associated with the effectiveness of radioembolization and related complications. By comprehensively analysing these factors, we aimed to provide a clearer understanding of how to optimise the use of SIRT in managing HCC patients, thereby enhancing outcomes across various clinical scenarios.

Update on PET Radiopharmaceuticals for Imaging Hepatocellular Carcinoma

Numerous positron emission tomography (PET) targets for detection and staging of hepatocellular cancer have been developed in recent years. Hepatocellular carcinomas (HCCs) are clinically and pathologically heterogeneous tumours with a high tendency to be aggressive and unresponsive to chemotherapy. Early detection is essential, and the need for an adequate imaging biomarker, which can overcome some of the limitations of conventional radiological imaging, is persistent. Flourine-18 (18F) flourodeoxyglucose (FDG), the most widely used PET radiopharmaceutical, has proven disappointing as a possible staple in the evaluation of HCC. This disappointment had led to experimentation with carious radiotracers, such as the choline derivatives, acetate, and prostate-specific membrane antigen, which appear to complement and/or enhance the role of FDG. In this study, we look at the various PET radiopharmaceuticals that have been used for imaging HCC and the particular pathways that they target in HCC and liver cancers.

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.

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.

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

BACKGROUND

Transarterial radioembolization (TARE) is widely used for the treatment of hepatocellular carcinoma (HCC), but early treatment response can be very difficult to assess. The aim was to evaluate 18F-fluorocholine PET/computed tomography (CT) to assess the treatment response in patients with intermediate or locally advanced HCC.

METHODS

Between March 2019 and July 2020, nine HCC patients treated with TARE, who underwent PET/CT at baseline and 1 month after treatment, were enrolled. The maximum, mean (SUVmean), and peak (SUVpeak) standardized uptake value (SUV), SUV normalized by lean body mass (SUL), and total lesion glycolysis (TLG) were measured. Statistical analysis used the Mann-Whitney test to evaluate the differences in parameters between responders (partial and complete response) and nonresponders (stable or progressive disease) at the 6-month follow-up, according to the modified Response Evaluation Criteria in Solid Tumors.

RESULTS

Three patients were nonresponders (progressive disease and stable disease) and six were responders. Delta SUVmean, delta SUL, and delta TLG could predict an early response (P = 0.02, P = 0.04, and P = 0.02, respectively). None of the pre-therapeutic parameters were correlated with the response. Post-therapeutic SUL, SUVmean, TLG, and SUVpeak were also predictive of the response.

CONCLUSIONS

Our preliminary results showed that changes in certain metabolic parameters (from baseline PET to 1-month PET) are predictive of the response to TARE in HCC (Delta SUVmean, delta TLG, and delta SUL). The absence of post-treatment inflammation could lead to a better prediction than MRI evaluation. This study suggests that 1-month 18F-choline PET/CT could modify the clinical management predicting responders.Video Abstract: http://links.lww.com/NMC/A193.

PET/CT-Based Response Evaluation in Cancer-a Systematic Review of Design Issues

Positron emission tomography/x-ray computed tomography (PET/CT) has long been discussed as a promising modality for response evaluation in cancer. When designing respective clinical trials, several design issues have to be addressed, especially the number/timing of PET/CT scans, the approach for quantifying metabolic activity, and the final translation of measurements into a rule. It is unclear how well these issues have been tackled in quest of an optimised use of PET/CT in response evaluation. Medline via Ovid and Science Citation Index via Web of Science were systematically searched for articles from 2015 on cancer patients scanned with PET/CT before and during/after treatment. Reports were categorised as being either developmental or evaluative, i.e. focusing on either the establishment or the evaluation of a rule discriminating responders from non-responders. Of 124 included papers, 112 (90 %) were accuracy and/or prognostic studies; the remainder were response-curve studies. No randomised controlled trials were found. Most studies were prospective (62 %) and from single centres (85 %); median number of patients was 38.5 (range 5-354). Most (69 %) of the studies employed only one post-baseline scan. Quantification was mainly based on SUVmax (91 %), while change over time was most frequently used to combine measurements into a rule (79 %). Half of the reports were categorised as developmental, the other half evaluative. Most development studies assessed only one element (35/62, 56 %), most frequently the choice of cut-off points (25/62, 40 %). In summary, the majority of studies did not address the essential open issues in establishing PET/CT for response evaluation. Reasonably sized multicentre studies are needed to systematically compare the many different options when using PET/CT for response evaluation.

Increased Bone Marrow 18F-Choline Uptake in a Patient with Hepatocellular Carcinoma and Thalassemia Intermedia

A 57-year-old male with history of thalassemia intermedia and hepatocellular carcinoma underwent a positron emission tomography/computed tomography (PET/CT) scan with ¹⁸F-choline before radioembolization procedure with ⁹⁰Y-microspheres. The PET/CT scan with ¹⁸F-choline demonstrated highly increased tracer incorporation within a gross lesion in the hepatic dome coupled with diffuse activity in bone marrow, this latter aspect was probably due to the compensatory hematopoiesis stimulation induced by chronic hemolysis. This pattern of skeletal ¹⁸F-choline uptake should be considered as a peculiar PET/CT finding in thalassemic patients.

Combined [18F]-Fluoroethylcholine PET/CT and 99mTc-Macroaggregated Albumin SPECT/CT Predict Survival in Patients With Intermediate-Stage Hepatocellular Carcinoma

AIM

The aim of this study was to retrospectively analyze the prognostic value of combined Tc-macroaggregated albumin (MAA) SPECT/CT and [F]-fluoroethylcholine (FEC) PET/CT before radioembolization for survival of patients with intermediate-stage hepatocellular carcinoma.

METHODS

Twenty-four patients with known hepatocellular carcinoma Barcelona Clinic Liver Cancer stage B were eligible for this analysis. All patients were scheduled for radioembolization and received a pretherapeutic [F]FEC PET/CT scan as well as Tc-MAA SPECT/CT for hepatopulmonary shunting. Laboratory and semiquantitative PET parameters and morphologic and metabolic (intersection) volumes of MAA and FEC were evaluated. Spearman correlation with overall survival, receiver operating curve analyses, univariate and multivariate Cox regression, and Kaplan-Meier-analysis was applied.

RESULTS

All patients (5 female/19 male) are deceased within the observational period. Median survival was 395 days (±51 days; range, 23-1122 days). The percentage of hypervascularized metabolically active tumor volume (vascularized tumor ratio; defined as high MAA and FEC uptake) correlated significantly with survival. Vascularized tumor ratio was a significant predictor in univariate and multivariate analyses (P = 0.026; hazard ratio, 11.65; 95% confidence interval, 1.62-83.73; P = 0.015). Statistical significance was not reached by all other variables in multivariate analysis. Receiver operating curve analysis for 1-year survival revealed an area under the curve of 0.77 (P = 0.024) for vascularized tumor ratio. At a cutoff value of 9%, sensitivity, specificity, and positive and negative prediction were 83%, 67%, and 71% and 80% (P = 0.036). Patients with a higher tumor vascularization had a median survival of 274 ± 80 versus 585 ± 284 days (P = 0.015).

CONCLUSIONS

Hepatocellular carcinoma with high vascularization in metabolic active areas as assessed by combined FEC PET/CT and Tc-MAA SPECT/CT represents an unfavorable subgroup with reduced overall survival after radioembolization.

18F-fluorodeoxyglucose uptake of hepatocellular carcinoma as a prognostic predictor in patients with sorafenib treatment

PURPOSE

Sorafenib, an oral multikinase inhibitor, is a recommended treatment option available for patients with Barcelona Clinic Liver Cancer (BCLC)-C stage hepatocellular carcinoma (HCC). This study aimed to evaluate the performance of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) for predicting tumour progression during sorafenib treatment.

METHODS

We formed a retrospective cohort comprising patients treated with sorafenib for at least 30 days and undergoing 18F-FDG PET/CT within 1 month before treatment. For statistical analyses, the tumour-to-liver standardised uptake value (SUV) ratio (TLR) of the most hypermetabolic lesion was measured.

RESULTS

Among a total of 35 patients, two obtained partial remission, and 11 showed stable disease after the first response evaluation. Patients with a TLR ≥ 2.9 (n = 17) had a median overall survival (OS) of 3.7 months after sorafenib treatment, whereas patients with a TLR < 2.9 (n = 18) had median OS of 12.2 months (P < 0.001), although the disease control rate was not significantly different between the two groups. Pretreatment TLR ≥ 2.9 (hazard ratio [HR] = 6.318, P = 0.002) and Child-Pugh class B (HR = 4.316, P = 0.044) were poor prognostic factors for OS, and a TLR ≥ 2.9 (HR = 2.911, P = 0.024) was the only poor prognostic factor for progression-free survival in a multivariate analysis.

CONCLUSION

Pretreatment tumour metabolic activity assessed by 18F-FDG PET is an independent prognostic factor for survival in patients with BCLC-C stage HCC receiving sorafenib monotherapy, although it may not predict tumour response to the treatment.

Radiological biomarkers for assessing response to locoregional therapies in hepatocellular carcinoma: From morphological to functional imaging (Review)

Many hepatocellular carcinoma (HCC) patients do not qualify for curative surgical intervention and are instead treated with locoregional therapies (LRTs) including ablative and endovascular therapies. Assessment of imaging response is essential in the management of HCC for determining efficacy of therapy and as a surrogate marker for improved survival. The established morphological image biomarkers for tumor burden measurement continue to be applied, as size measurement can easily be used in clinical practice. However, in the setting of liver-directed LRTs for HCC, simple tumor morphological changes can be less informative and usually appear later than biologic changes. Functional imaging (such as perfusion and diffusion imaging, PET-CT/MR and MR spectroscopy) has the potential to be a promising technique for assessment of HCC response to LRTs. Although promising, none of these functional imaging biomarkers have gone through all the required steps of standardization and validation and established accepted criteria for clinical practice.

Superfluorinated PEI Derivative Coupled with (99m) Tc for ASGPR Targeted (19) F MRI/SPECT/PA Tri-Modality Imaging

Fluorinated polyethylenimine derivative labeled with radionuclide (99m) Tc is developed as a (19) F MRI/SPECT/PA multifunctional imaging agent with good asialoglycoprotein receptors (ASGPR)-targeting ability. This multifunctional agent is safe and suitable for (19) F MRI/SPECT/PA imaging and has the potential to detect hepatic diseases and to assess liver function, which provide powerful support for the development of personalized and precision medicine.

Hepatic imaging following intra-arterial embolotherapy

PURPOSE

To discuss guidelines and salient imaging findings of solid tumors treated with common intra-arterial procedures used in interventional oncology.

METHODS

A meticulous literature search of PubMed-indexed articles was conducted. Key words included "imaging + embolization," "imaging + TACE," "imaging + radioembolization," "imaging + Y90," "mRECIST," and "EASL." Representative post-treatment cross-sectional images were obtained from past cases in this institution.

RESULTS

Intra-arterial therapy (IAT) in interventional oncology includes bland embolization, chemoembolization, and radioembolization. Solid tumors of the liver are the primary focus of these procedures. Cross-sectional CT and/or MR are the main modalities used to image tumors after treatment. Traditional size-based response criteria (WHO and RECIST) alone are of limited utility in determining response to IAT; tumoral necrosis and enhancement must be considered. Specifically for HCC, the EASL and mRECIST guidelines are becoming widely adopted response criteria to assess these factors. DWI, FDG-PET, and CEUS are modalities that play an adjunctive but controversial role.

CONCLUSIONS

Radiologists must be aware that the different forms of intra-arterial therapy yield characteristic findings on cross-sectional imaging. Knowledge of these findings is integral to accurate assessment of tumor response and progression.

Recurrent Extrahepatic Hepatocellular Carcinoma Detected by 18F-Choline PET/CT

Diagnosis of recurrent hepatocellular carcinoma (HCC) is sometimes challenging, especially when extrahepatic disease is present. Here, we report on a 49-year-old woman with a history of HCC who was referred to our institution with suspicion of tumor recurrence for further workup. Combined F-choline PET/CT revealed a soft tissue mass at the right thoracic wall highly consistent with HCC.

[Combined PET-MRI of the abdomen]

The first fully integrated combined positron emission tomography-magnetic resonance imaging (PET-MRI) scanners have been clinically available since 2010. Large prospective studies regarding indications and diagnostic accuracy of this new modality are not yet available; however, preliminary studies have shown a higher diagnostic accuracy and confidence compared to PET-computed tomography (PET-CT) in regions where MRI is known to be superior to CT, such as the liver. The benefit of MRI in accurate lesion characterization and the additional value of diffusion-weighted imaging (DWI) as a complementary functional modality by means of the apparent diffusion coefficient (ADC) is apparent in entities with low tracer uptake (e.g. due to small size) and a decreased or absent accumulation pattern on PET.