11C-acetate and 18F-FDG PET/CT for clinical staging and selection of patients with hepatocellular carcinoma for liver transplantation on the basis of Milan criteria: surgeon's perspective

Role of molecular imaging in prognosis, diagnosis, and treatment of gastrointestinal cancers: An update on new therapeutic methods

One of the leading causes of cancer-related death is gastrointestinal cancer, which has a significant morbidity and mortality rate. Although preoperative risk assessment is essential for directing patient care, its biological behavior cannot be accurately predicted by conventional imaging investigations. Potential pathophysiological information in anatomical imaging that cannot be visually identified can now be converted into high-dimensional quantitative image features thanks to the developing discipline of molecular imaging. In order to enable molecular tissue profile in vivo, molecular imaging has most recently been utilized to phenotype the expression of single receptors and targets of biological therapy. It is expected that molecular imaging will become increasingly important in the near future, driven by the expanding range of biological therapies for cancer. With this live molecular fingerprinting, molecular imaging can be utilized to drive expression-tailored customized therapy. The technical aspects of molecular imaging are first briefly discussed in this review, followed by an examination of the most recent research on the diagnosis, prognosis, and potential future clinical methods of molecular imaging for GI tract malignancies.

Qualitative and quantitative differentiation efficiency of dual-tracer PET/CT with 18F-fluorodeoxyglucose and 11C-acetate for primary hepatocellular carcinoma: a systematic review and meta-analysis

PURPOSE

Primary hepatocellular carcinoma (HCC) represents a substantial global health challenge. Early diagnosis of HCC is crucial for improved patient outcomes. The aim of this study was to assess qualitative and quantitative diagnostic performance of PET/CT using 11C-acetate and [18F]-fluorodeoxyglucose (FDG) in detection of primary HCC and to determine if 11C-acetate added to [18F]-FDG alleviates the low sensitivity rate mentioned in guidelines.

METHODS

Protocol was pre-registered at https://osf.io/2vcb9 . We searched PubMed, Web of Science, Embase, and the Cochrane Library for included studies. Quality Assessment of Diagnostic Accuracy Studies 2 was used to assess the risk of bias. Possible sources of statistical heterogeneity were explored. Additionally, mentioned three PET/CT tests were evaluated for their diagnostic performance in differentiating HCC from its differential diagnoses. Grades of Recommendation, Assessment, Development, and Evaluation was used to assess quality of generated evidence.

RESULTS

Twenty-four studies were analyzed. Qualitative dual-tracer PET/CT demonstrated 92.0% per-lesion sensitivity, and a significantly higher direct sensitivity difference of 30% to conventional CT, 44.7% to [18F]-FDG, and 12.0% to 11C-acetate. Regarding differentiation rate, [18F]-FDG was superior to 11C-acetate in poorly differentiated lesions while 11C-acetate was superior in well-differentiated lesions. Regarding size, dual tracer combination solved the high missing rate of HCC lesions in 1-2 cm and 2-5 cm groups but could not help in size < 1 cm.

CONCLUSION

Dual-tracer PET/CT utilizing 11C-acetate and [18F]-FDG represents a sensitive method for detecting primary HCC. By concurrently quantifying or qualifying the uptake of 11C-acetate and [18F]-FDG, this multimodal approach enables precise localization of intrahepatic lesions.

Dual-tracer PET/CT in the management of hepatocellular carcinoma

Background & Aims

Combined 18F-fluorodeoxyglucose (FDG) and 11C-acetate (dual-tracer) positron-emission tomography/computed tomography (PET/CT) is being increasingly performed for the management of hepatocellular carcinoma (HCC), although its role is not well defined. Therefore, we evaluated its effectiveness in (i) staging, (ii) characterization of indeterminate lesions on conventional imaging, and (iii) detection of HCC in patients with unexplained elevations in serum alpha-fetoprotein (AFP) levels.

Methods

We retrospectively assessed 525 consecutive patients from three tertiary centers between 2014 and 2020. For staging, we recorded new lesion detection rates, changes in the Barcelona Clinic Liver Cancer (BCLC) classification, and treatment allocation due to dual-tracer PET/CT. To characterize indeterminate lesions and unexplained elevation of serum AFP levels, the sensitivity and specificity of dual-tracer PET/CT in diagnosing HCC were evaluated. A multidisciplinary external review and a cost-benefit analysis of patients for metastatic screening were also performed.

Results

Dual-tracer PET/CT identified new lesions in 14.3% of 273 staging patients, resulting in BCLC upstaging in 11.7% and treatment modifications in 7.7%. It upstaged 8.1% of 260 patients undergoing metastatic screening, with estimated savings of US$495 per patient. It had a sensitivity and specificity of 80.7% (95% CI 71.2-88.6%) and 94.8% (95% CI 90.4-98.6%), respectively, for diagnosing HCC in 201 indeterminate lesions. It detected HCC in 45.1% of 51 patients with unexplained elevations in serum AFP concentrations. External review revealed substantial agreement between local and external image interpretation and patient assessment (n = 273, κ = 0.822; 95% CI 0.803-0.864).

Conclusions

Dual-tracer PET/CT provides added value beyond conventional imaging in patients with HCC by improving staging, confirming HCC diagnosis with high accuracy in patients with indeterminate lesions, and detecting HCC in patients with unexplained elevation of serum AFP.

Impact and implications

Compared to CT or MRI, dual-tracer positron-emission tomography/computed tomography (PET/CT) led to upstaging in 12% of patients with hepatocellular carcinoma (HCC) undergoing staging, resulting in treatment modification in 8% of cases and a cost saving of US$495 per patient. It also accurately detected HCC in high-risk cases where CT or MRI were equivocal or normal. Dual-tracer PET/CT provides added value beyond conventional imaging in patients with HCC by improving staging, confirming HCC diagnosis with high accuracy in patients with indeterminate lesions, and detecting HCC in patients with unexplained elevation of serum AFP.

Advances in gross tumor target volume determination in radiotherapy for patients with hepatocellular carcinoma

Hepatocellular Carcinoma (HCC) is one of the most common malignant neoplasms. With the advancement of technology, the precision of radiotherapy (RT) for HCC has considerably increased, and it is an indispensable modality in the comprehensive management of HCC. Some RT techniques increase the radiation dose to HCC, which decreases the radiation dose delivered to the surrounding normal liver tissue. This approach significantly improves the efficacy of HCC treatment and reduces the incidence of Radiation-induced Liver Disease (RILD). Clear imaging and precise determination of the Gross Target Volume (GTV) are prerequisites of precise RT of HCC. The main hindrances in determining the HCC GTV include indistinct tumor boundaries on imaging and the impact on respiratory motion. The integration of multimodal imaging, four-dimensional imaging, and artificial intelligence (AI) techniques can help overcome challenges for HCC GTV. In this article, the advancements in medical imaging and precise determination for HCC GTV have been reviewed, providing a framework for the precise RT of HCC.

Guidelines for the Diagnosis and Treatment of Primary Liver Cancer (2022 Edition)

Background

Primary liver cancer, of which around 75-85% is hepatocellular carcinoma in China, is the fourth most common malignancy and the second leading cause of tumor-related death, thereby posing a significant threat to the life and health of the Chinese people.

Summary

Since the publication of Guidelines for Diagnosis and Treatment of Primary Liver Cancer in China in June 2017, which were updated by the National Health Commission in December 2019, additional high-quality evidence has emerged from researchers worldwide regarding the diagnosis, staging, and treatment of liver cancer, that requires the guidelines to be updated again. The new edition (2022 Edition) was written by more than 100 experts in the field of liver cancer in China, which not only reflects the real-world situation in China but also may reshape the nationwide diagnosis and treatment of liver cancer.

Key Messages

The new guideline aims to encourage the implementation of evidence-based practice and improve the national average 5-year survival rate for patients with liver cancer, as proposed in the "Health China 2030 Blueprint."

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.

The Complementary Role of PET to Pathology in Differentiating the Primary Origin of a Malignant Skin Nodule from Liver or Lung

Metastasis from unknown primary is always a challenge because finding the true primary tumor significantly affects subsequent management. We present a case of malignant abdominal wall nodule initially diagnosed as metastasis from hepatocellular carcinoma through excisional biopsy and immunohistochemical (IHC) staining. Dual-tracer positron emission tomography/computed tomography (PET/CT) with 11C-acetate and 18F-FDG, however, showed metabolic findings in favor of metastasis from lung origin, which was finally confirmed by ensuing a lung biopsy with additional IHC stains. This case illustrates the complementary molecular role of PET to pathology, particularly when dual-tracer or multi-tracer PET is used in conjunction with pathology methods for cross referencing and confirmation.

Primary Tumor Radiomic Model for Identifying Extrahepatic Metastasis of Hepatocellular Carcinoma Based on Contrast Enhanced Computed Tomography

This study aimed to identify radiomic features of primary tumor and develop a model for indicating extrahepatic metastasis of hepatocellular carcinoma (HCC). Contrast-enhanced computed tomographic (CT) images of 177 HCC cases, including 26 metastatic (MET) and 151 non-metastatic (non-MET), were retrospectively collected and analyzed. For each case, 851 radiomic features, which quantify shape, intensity, texture, and heterogeneity within the segmented volume of the largest HCC tumor in arterial phase, were extracted using Pyradiomics. The dataset was randomly split into training and test sets. Synthetic Minority Oversampling Technique (SMOTE) was performed to augment the training set to 145 MET and 145 non-MET cases. The test set consists of six MET and six non-MET cases. The external validation set is comprised of 20 MET and 25 non-MET cases collected from an independent clinical unit. Logistic regression and support vector machine (SVM) models were identified based on the features selected using the stepwise forward method while the deep convolution neural network, visual geometry group 16 (VGG16), was trained using CT images directly. Grey-level size zone matrix (GLSZM) features constitute four of eight selected predictors of metastasis due to their perceptiveness to the tumor heterogeneity. The radiomic logistic regression model yielded an area under receiver operating characteristic curve (AUROC) of 0.944 on the test set and an AUROC of 0.744 on the external validation set. Logistic regression revealed no significant difference with SVM in the performance and outperformed VGG16 significantly. As extrahepatic metastasis workups, such as chest CT and bone scintigraphy, are standard but exhaustive, radiomic model facilitates a cost-effective method for stratifying HCC patients into eligibility groups of these workups.

Hepatic Positron Emission Tomography: Applications in Metabolism, Haemodynamics and Cancer

Evaluating in vivo the metabolic rates of the human liver has been a challenge due to its unique perfusion system. Positron emission tomography (PET) represents the current gold standard for assessing non-invasively tissue metabolic rates in vivo. Here, we review the existing literature on the assessment of hepatic metabolism, haemodynamics and cancer with PET. The tracer mainly used in metabolic studies has been [¹⁸F]2-fluoro-2-deoxy-D-glucose (¹⁸F-FDG). Its application not only enables the evaluation of hepatic glucose uptake in a variety of metabolic conditions and interventions, but based on the kinetics of ¹⁸F-FDG, endogenous glucose production can also be assessed. 14(R,S)-[¹⁸F]fluoro-6-thia-Heptadecanoic acid (¹⁸F-FTHA), ¹¹C-Palmitate and ¹¹C-Acetate have also been applied for the assessment of hepatic fatty acid uptake rates (¹⁸F-FTHA and ¹¹C-Palmitate) and blood flow and oxidation (¹¹C-Acetate). Oxygen-15 labelled water (¹⁵O-H₂O) has been used for the quantification of hepatic perfusion. ¹⁸F-FDG is also the most common tracer used for hepatic cancer diagnostics, whereas ¹¹C-Acetate has also shown some promising applications in imaging liver malignancies. The modelling approaches used to analyse PET data and also the challenges in utilizing PET in the assessment of hepatic metabolism are presented.

Comparison of 18F-FDG, 18F-Fluoroacetate, and 18F-FEPPA for Imaging Liver Fibrosis in a Bile Duct-Ligated Rat Model

Developing sensitive diagnostic methods for a longitudinal evaluation of the status of liver fibrosis is a priority. This study is aimed at assessing the significance of longitudinal positron emission tomography (PET) imaging with ¹⁸F-labeling tracers for assessing liver fibrosis in a rat model with bile duct ligation (BDL). Twenty-one 6-week-old Sprague-Dawley male rats were used in this study. Longitudinal PET images using [¹⁸F]N-2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide ([¹⁸F]FEPPA) (n = 3), [¹⁸F]fluoroacetate ([¹⁸F]FAc) (n = 3), and 18F-fluoro-2-deoxy-D-glucose ([¹⁸F]FDG) (n = 3) were obtained at 0, 1, and 2 weeks after BDL. Biochemical assays, histological assays, immunohistochemical staining assays, and next generation sequencing analyses were also performed at 0 (n = 3), 1 (n = 3), 2 (n = 3), and 3 (n = 3) weeks after BDL, which demonstrated the severe damage in rat livers after BDL. Regarding [¹⁸F]FEPPA and [¹⁸F]FDG, there was a significantly higher uptake in the liver after BDL (both P < 0.05), which lasted until week 2. However, the uptake of [¹⁸F]FAc in the liver was not significantly different before and after BDL (P = 0.28). Collectively, both [¹⁸F]FEPPA and [¹⁸F]FDG can serve as sensitive probes for detecting the liver fibrosis. However, [¹⁸F]FAc is not recommended to diagnose liver fibrosis.

Performance of Dual-tracer PET-CT for Staging Post-Liver Transplant Hepatocellular Carcinoma Recurrence

Precise staging is essential in the management of patients with recurrent hepatocellular carcinoma (HCC) after liver transplantation. There is no current consensus on the optimal staging strategy. We conducted this study to evaluate the performance of dual-tracer positron emission tomography-computed tomography (PET-CT) for this purpose and to investigate whether the results of dual-tracer PET-CT affected patient management.

Methods

A retrospective study was conducted. Patients who underwent dual-tracer PET-CT for suspected or confirmed HCC recurrence after liver transplant were included. The lesion-based sensitivity and positive predictive value of dual-tracer PET-CT were determined.

Results

Fifty-six patients and 189 recurrent tumors were included. The lesion-based sensitivity and positive predictive value of dual-tracer PET-CT were 94.7% and 90.4%, respectively. The sensitivity of dual-tracer PET-CT was better than the standard imaging in the surveillance protocol (82.5% versus 94.7%, P < 0.001), especially for detecting liver recurrence (71.0% versus 96.8%, P < 0.001). Half of the dual-tracer PET-CT detected additional recurrence (n = 26, 46.4%) and one-third led to a change in management (n = 19, 33.9%). Ten patients (17.9%) with inconclusive standard imaging had metabolic recurrence confirmed on PET-CT and treatment was commenced early. Four patients (7.1%) had revised locoregional treatment, and 5 (8.9%) had to withdraw from locoregional treatment after the detection of additional metastatic disease.

Conclusions

Dual-tracer PET-CT is effective for staging posttransplant HCC recurrence. It often provides valuable information to guide clinical management.

Immunological Markers, Prognostic Factors and Challenges Following Curative Treatments for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortalities worldwide. Patients with early-stage HCC are eligible for curative treatments, such as surgical resection, liver transplantation (LT) and percutaneous ablation. Although curative treatments provide excellent long-term survival, almost 70–80% of patients experience HCC recurrence after curative treatments. Tumor-related factors, including tumor size, number and differentiation, and underlying liver disease, are well-known risk factors for recurrence following curative therapies. Moreover, the tumor microenvironment (TME) also plays a key role in the recurrence of HCC. Many immunosuppressive mechanisms, such as an increase in regulatory T cells and myeloid-derived suppressor cells with a decrease in cytotoxic T cells, are implicated in HCC recurrence. These suppressive TMEs are also modulated by several factors and pathways, including mammalian target of rapamycin signaling, vascular endothelial growth factor, programmed cell death protein 1 and its ligand 1. Based on these mechanisms and the promising results of immune checkpoint blockers (ICBs) in advanced HCC, there have been several ongoing adjuvant studies using a single or combination of ICB following curative treatments in HCC. In this review, we strive to provide biologic and immunological markers, prognostic factors, and challenges associated with clinical outcomes after curative treatments, including resection, LT and ablation.

Current Trends in Non-Invasive Imaging of Interactions in the Liver Tumor Microenvironment Mediated by Tumor Metabolism

With the increasing understanding of resistance mechanisms mediated by the metabolic reprogramming in cancer cells, there is a growing clinical interest in imaging technologies that allow for the non-invasive characterization of tumor metabolism and the interactions of cancer cells with the tumor microenvironment (TME) mediated through tumor metabolism. Specifically, tumor glycolysis and subsequent tissue acidosis in the realms of the Warburg effect may promote an immunosuppressive TME, causing a substantial barrier to the clinical efficacy of numerous immuno-oncologic treatments. Thus, imaging the varying individual compositions of the TME may provide a more accurate characterization of the individual tumor. This approach can help to identify the most suitable therapy for each individual patient and design new targeted treatment strategies that disable resistance mechanisms in liver cancer. This review article focuses on non-invasive positron-emission tomography (PET)- and MR-based imaging techniques that aim to visualize the crosstalk between tumor cells and their microenvironment in liver cancer mediated by tumor metabolism.

68Ga-FAPI-04 Versus 18F-FDG PET/CT in the Detection of Hepatocellular Carcinoma

Background

Fibroblast activation protein (FAP) is commonly expressed in activated stromal fibroblasts in various epithelial tumours. Recently, ⁶⁸Ga-FAPI-04 has been used for tumour imaging in positron emission tomography/computed tomography (PET/CT). This study aimed to compare the diagnostic performances of ⁶⁸Ga-FAPI-04 PET/CT and ¹⁸F-FDG PET/CT in hepatocellular carcinoma (HCC), and to assess factors associated with ⁶⁸Ga-FAPI-04 uptake in HCC.

Materials and Methods

Twenty-nine patients with suspiciously HCC who received both ¹⁸F-FDG and ⁶⁸Ga-FAPI-04 PET/CT were included in this retrospective study. The results were interpreted by two experienced nuclear medicine physicians independently. The maximum and mean standardized uptake values (SUV_max and SUV_mean) were measured in the lesions and liver background, respectively. The tumour-to-background ratio (TBR) was then calculated as lesion's SUV_max divided by background SUV_mean.

Results

A total of 35 intrahepatic lesions in 25 patients with HCC were finally involved in the statistical analysis. ⁶⁸Ga-FAPI-04 PET/CT showed a higher sensitivity than ¹⁸F-FDG PET/CT in detecting intrahepatic HCC lesions (85.7% vs. 57.1%, P = 0.002), including in small (≤ 2 cm in diameter; 68.8% vs. 18.8%, P = 0.008) and well- or moderately-differentiated (83.3% vs. 33.3%, P = 0.031) tumors. SUV_max was comparable between ⁶⁸Ga-FAPI-04 and ¹⁸F-FDG (6.96 ± 5.01 vs. 5.89 ± 3.38, P > 0.05), but the TBR was significantly higher in the ⁶⁸Ga-FAPI-04 group compared with the ¹⁸F-FDG group (11.90 ± 8.35 vs. 3.14 ± 1.59, P < 0.001). SUV_max and the TBR in ⁶⁸Ga-FAPI-04 positive lesions were associated with tumour size (both P < 0.05), but not the remaining clinical and pathological features (all P > 0.05).

Conclusions

⁶⁸Ga-FAPI-04 PET/CT is more sensitive than ¹⁸F-FDG PET/CT in detecting HCC lesions, and ⁶⁸Ga-FAPI-04 uptake is correlated mainly with tumour size.

Extrahepatic metastases from hepatocellular carcinoma: multimodality image evaluation

The most prevalent primary malignancy of the liver is hepatocellular carcinoma (HCC); its poor prognosis is mainly related to intrahepatic recurrence and extrahepatic metastases. However, survival from HCC has improved due to better control of the primary tumor, the development of newer treatment modalities, including liver transplant, together with advances in imaging techniques. Therefore, the significance of patient management as corresponds with distant metastases has increased; since the proper evaluation and detection of extrahepatic metastases is crucial to optimize potential therapy for patients. Conventional imaging like CT, MRI play crucial rule in patient's diagnosis and qualifying for a certain type of therapy. More recently, a molecular imaging tool with radiolabeled deoxyglucose and fluorocholine has proved its promising value as a complementary tool to conventional studies. In this review, the frequent sites of metastases and HCC spread are discussed as well as the imaging findings as seen by both conventional imaging techniques and by molecular imaging tools, namely 18F-Choline PET/CT, and FDG PET. The implications of guiding treatment planning have also been discussed.

Role of C11-FDG dual-tracer PET-CT scan in metastatic screening of hepatocellular carcinoma-a cost-effectiveness analysis

Background

We aimed to identify predictive factors for positron emission tomography (PET)-detected hepatocellular carcinoma (HCC) metastasis and a cost-effective approach to preoperative PET-computed tomography (CT) for detecting metastasis.

Methods

Clinicopathological and survival data of HCC patients having PET-CT with 18F-fludeoxyglucose (FDG) and 11C-acetate (ACT) following contrast-enhanced CT/magnetic resonance imaging (MRI) for preoperative tumor staging were reviewed. Binary logistic regression was performed to identify predictive factors for PET-detected metastasis. A cost-benefit analysis model was built for the incurred costs and the impact of PET-CT findings on treatment strategy was studied.

Results

Totally 152 patients were analyzed. Dual-tracer PET-CT detected metastasis in 17 patients (11%). By multivariate analysis, alpha-fetoprotein (AFP) ≥400 ng/mL [relative risk (RR): 4.30, 95% confidence interval (CI): 1.41-13.15, P=0.011] and bilobar disease (RR: 3.94, 95% CI: 1.24-12.52, P=0.014) were independent predictive factors for PET-detected metastasis. PET-CT findings altered the treatment strategy for 12 patients (7.9%); three partial hepatectomies, eight episodes of transarterial chemoembolization (TACE) and one episode of ablation were avoided, with an estimated cost-saving of US $91,000, $150,000 and $10,600 respectively. Had the PET-CT been performed only for patients with AFP ≥400 ng/mL or bilobar disease (n=74), metastasis would have been confirmed in 14 patients (18.9%), and the cost-saving per patient was estimated at US $1,070.

Conclusions

Dual-tracer PET-CT is cost-effective and useful for preoperative HCC staging in patients with AFP ≥400 ng/mL or bilobar disease. Its routine use in preoperative workup for all HCC patients is not recommended. Unilobar disease with AFP <400 ng/mL can achieve good negative predictive value for PET-detected metastasis. Screening patients with either factor can avoid unnecessary procedures and is thus cost-effective for preoperative HCC workup.

Biological Evaluation of [18F]AlF-NOTA-NSC-GLU as a Positron Emission Tomography Tracer for Hepatocellular Carcinoma

Purpose: N-(2-[¹⁸F]fluoropropionyl)-L-glutamate ([¹⁸F]FPGLU) for hepatocellular carcinoma (HCC) imaging has been performed in our previous studies, but its radiosynthesis method and stability in vivo need to be improved. Hence, we evaluated the synthesis and biological properties of a simple [¹⁸F]-labeled glutamate analog, [¹⁸F]AlF-1,4,7-triazacyclononane-1,4,7-triacetic-acid-2-S-(4-isothiocyanatobenzyl)-l-glutamate ([¹⁸F]AlF-NOTA-NSC-GLU), for HCC imaging.

Procedures: [¹⁸F]AlF-NOTA-NSC-GLU was synthesized via a one-step reaction sequence from NOTA-NSC-GLU. In order to investigate the imaging value of [¹⁸F]AlF-NOTA-NSC-GLU in HCC, we conducted positron emission tomography/computed tomography (PET/CT) imaging and competitive binding of [¹⁸F]AlF-NOTA-NSC-GLU in human Hep3B tumor-bearing mice. The transport mechanism of [¹⁸F]AlF-NOTA-NSC-GLU was determined by competitive inhibition and protein incorporation experiments in vitro.

Results: [¹⁸F]AlF-NOTA-NSC-GLU was prepared with an overall radiochemical yield of 29.3 ± 5.6% (n = 10) without decay correction within 20 min. In vitro competitive inhibition experiments demonstrated that the Na⁺-dependent systems XAG-, B0⁺, ASC, and minor XC- were involved in the uptake of [¹⁸F]AlF-NOTA-NSC-GLU, with the Na⁺-dependent system XAG- possibly playing a more dominant role. Protein incorporation studies of the Hep3B human hepatoma cell line showed almost no protein incorporation. Micro-PET/CT imaging with [¹⁸F]AlF-NOTA-NSC-GLU showed good tumor-to-background contrast in Hep3B human hepatoma-bearing mouse models. After [¹⁸F]AlF-NOTA-NSC-GLU injection, the tumor-to-liver uptake ratio of [¹⁸F]AlF-NOTA-NSC-GLU was 2.06 ± 0.17 at 30 min post-injection. In vivo competitive binding experiments showed that the tumor-to-liver uptake ratio decreased with the addition of inhibitors to block the X_AG system.

Conclusions: We have successfully synthesized [¹⁸F]AlF-NOTA-NSC-GLU as a novel PET tracer with good radiochemical yield and high radiochemical purity. Our findings indicate that [¹⁸F]AlF-NOTA-NSC-GLU may be a potential candidate for HCC imaging. Also, a further biological evaluation is underway.

Gastric wall metastases from hepatocellular carcinoma: case report and review of the literature

A 69-year-old male patient who had a history of well-differentiated hepatocellular carcinoma (HCC) post right hepatectomy presented a year later with iron-deficiency anemia. His anemia work-up included upper endoscopy that revealed multiple gastric polyp a biopsy from the largest demonstrated metastatic hepatocellular carcinoma. His magnetic resonance imaging (MRI) showed a gastric "polyp" without evidence of local HCC recurrence within the liver. His subsequent dual imaging with Choline/fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) confirmed the gastric metastases and in addition revealed other sites of unexpected metastatic disease in the right adrenal and the bone that was asymptomatic. Patient was started on sorafenib and currently he is alive one-and-half-year postdetection of his metastatic disease under palliative care. This case showed that the possibility of gastric metastases should be kept in mind when confronted with anemia in HCC patient and also highlight the complementary role of molecular imaging modality along with MRI in the metastatic work-up for hepatocellular carcinoma postcurative resection.

Prognostic Value of Preoperative Serum Leucine Aminopeptidases in Hepatocellular Carcinoma Patients Who Underwent Liver Transplantation

Background

Leucine aminopeptidases (LAPs) have been reported to be involved in tumor cell proliferation, invasion and angiogenesis. However, the relationship between serum leucine aminopeptidases and prognosis of hepatocellular carcinoma (HCC) patients who underwent liver transplantation (LT) was not yet reported. We aimed to evaluate the prognostic value of preoperative serum leucine aminopeptidases in these patients.

Methods

Clinical data of 106 HCC patients who underwent LT were retrospectively analyzed. The sex ratio, age, HBV infection, Child-Pugh stage, preoperative tumor therapy, AFP, the largest tumor size, tumor number, Edmondson grading, macro- and micro-vascular invasion of patients with different serum LAP level and compositions of patients who met the criteria of Milan, UCSF or Hangzhou were compared using the chi-square test. The Kaplan-Meier method was performed in survival analysis and the log rank test was used in survival comparison.

Results

Serum LAPs were correlated with alpha-fetoprotein (AFP), the largest tumor size, tumor number and macro-vascular invasion. Patients with serum LAPs > 87 U/L showed significantly poorer disease-free survival (DFS) and overall survival (OS) than those with serum LAPs ≤ 87 U/L. Univariate analysis indicated that serum LAPs, AFP, the largest tumor size, tumor number, and macro- and micro-vascular invasion were all associated with DFS and OS. Multivariate analysis showed that serum LAPs, macro-vascular invasion and the largest tumor size were independently correlated with DFS and OS. Serum LAPs could also distinguish prognosis between patients with different status of AFP, the largest tumor size, tumor number, and macro- and micro-vascular invasion, as well as patients within and beyond selection criteria, such as Milan, University of California, San Francisco and Hangzhou criteria.

Conclusion

Elevated preoperative serum LAPs were associated with advanced tumor stage and aggressive biological behavior, and thus a poor outcome, which could be a prognostic marker for HCC patients who underwent LT.

Guidelines for the Diagnosis and Treatment of Hepatocellular Carcinoma (2019 Edition)

BACKGROUND

Primary liver cancer, around 90% are hepatocellular carcinoma in China, is the fourth most common malignancy and the second leading cause of tumor-related death, thereby posing a significant threat to the life and health of the Chinese people.

SUMMARY

Since the publication of Guidelines for Diagnosis and Treatment of Primary Liver Cancer (2017 Edition) in 2018, additional high-quality evidence has emerged with relevance to the diagnosis, staging, and treatment of liver cancer in and outside China that requires the guidelines to be updated. The new edition (2019 Edition) was written by more than 70 experts in the field of liver cancer in China. They reflect the real-world situation in China regarding diagnosing and treating liver cancer in recent years.

KEY MESSAGES

Most importantly, the new guidelines were endorsed and promulgated by the Bureau of Medical Administration of the National Health Commission of the People's Republic of China in December 2019.

Pure laparoscopic versus open major hepatectomy for hepatocellular carcinoma with liver F4 cirrhosis without routine Pringle maneuver - A propensity analysis in a single center

BACKGROUND

/Aim: Laparoscopic hepatectomy has been gaining popularity but its evidence in major hepatectomy for cirrhotic liver is lacking. We studied the long-term outcomes of the pure laparoscopic approach versus the open approach in major hepatectomy without Pringle maneuver in patients with hepatocellular carcinoma (HCC) and cirrhosis using the propensity score analysis.

METHODS

We reviewed patients diagnosed with HCC and cirrhosis who underwent major hepatectomy as primary treatment. The outcomes of patients who received the laparoscopic approach were compared with those of propensity-case-matched patients (ratio, 4:1) who received the open approach. The matching was made on the following factors: tumor size, tumor number, age, sex, hepatitis serology, HCC staging, comorbidity, and liver function.

RESULTS

Twenty-four patients underwent pure laparoscopic major hepatectomy for HCC with cirrhosis. Ninety-six patients who underwent open major hepatectomy were matched by propensity scores. The laparoscopic group had less median blood loss (300 ml vs 645 ml, p = 0.001), shorter median hospital stay (6 days vs 10 days, p = 0.002), and lower rates of overall complication (12.5% vs 39.6%, p = 0.012), pulmonary complication (4.2% vs 25%, p = 0.049) and pleural effusion (p = 0.026). The 1-year, 3-year and 5-year overall survival rates in the laparoscopic group vs the open group were 95.2%, 89.6% and 89.6% vs 87.5%, 72.0% and 62.8% (p = 0.211). Correspondingly, the disease-free survival rates were 77.1%, 71.2% and 71.2% vs 75.8%, 52.7% and 45.5% (p = 0.422).

CONCLUSIONS

The two groups had similar long-term survival. The laparoscopic group had favorable short-term outcomes. Laparoscopic major hepatectomy without routine Pringle maneuver for HCC with cirrhosis is a safe treatment option at specialized centers.

Molecular Imaging and Therapy of Liver Tumors

Liver cancer is one of the top leading causes of mortality worldwide. Conventional imaging using contrast enhanced CT and MRI are currently the mainstay of oncologic imaging of the liver for the diagnosis and management of cancer. In the past two decades, especially since the advent of hybrid imaging in the form of PET/CT and SPECT/CT, molecular imaging has been increasingly utilized for oncologic imaging and the variety of radionuclide probes for imaging liver cancers have been expanding. Beyond the usual workhorse of FDG as an oncologic tracer, there is a growing body of evidence showing that radiolabeled choline tracers, C-11 acetate and other new novel tracers may have increasing roles to play for the imaging of liver tumors. On the therapy front, there have also been advances in recent times in terms of targeted therapies for both primary and secondary liver malignancies, particularly with transarterial radioembolization. The concept of theranostics can be applied to transarterial radioembolization by utilizing a pretreatment planning scan, such as Tc-99m macroaggregated albumin scintigraphy, coupled with post treatment imaging. Radiation dose planning by personalized dosimetric calculations to the liver tumors is also being advocated. This article explores the general trends in the field of nuclear medicine for the imaging and treatment of liver cancer above and beyond routine diagnosis and management.

Utility of positron emission tomography-computed tomography scan in detecting residual hepatocellular carcinoma post treatment: Series of case reports

BACKGROUND

Multi-phase computed tomography (CT) or magnetic resonance imaging (MRI) has been the standard of care for hepatocellular carcinoma (HCC) diagnosis for years.

CASE SUMMARY

We report a case series of four patients in whom positron emission tomography-computed tomography (PET-CT) scan complemented the conventional CT/MRI scans in evaluating treatment response. In these four cases the conventional multi-phase CT and MRI failed to identify residual HCC disease post-treatment, while PET-CT complemented and aided in treatment response evaluation. In each case, the addition of PET-CT identified and located residual HCC disease, allowed retreatment, and altered medical management.

CONCLUSION

This case series suggests that PET-CT should perhaps play a role in the HCC management algorithm, in addition to the conventional contrast-enhanced multi-phase scans.

Advances in the early diagnosis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers globally. In contrast to the declining death rates observed for all other common cancers such as breast, lung, and prostate cancers, the death rates for HCC continue to increase by ~2–3% per year because HCC is frequently diagnosed late and there is no curative therapy for an advanced HCC. The early diagnosis of HCC is truly a big challenge. Over the past years, the early diagnosis of HCC has relied on surveillance with ultrasonography (US) and serological assessments of alpha-fetoprotein (AFP). However, the specificity and sensitivity of US/AFP is not satisfactory enough to detect early onset HCC. Recent technological advancements offer hope for early HCC diagnosis. Herein, we review the progress made in HCC diagnostics, with a focus on emerging imaging techniques and biomarkers for early disease diagnosis.

Metal-Based Complexes as Pharmaceuticals for Molecular Imaging of the Liver

This article reviews the use of metal complexes as contrast agents (CA) and radiopharmaceuticals for the anatomical and functional imaging of the liver. The main focus was on two established imaging modalities: magnetic resonance imaging (MRI) and nuclear medicine, the latter including scintigraphy and positron emission tomography (PET). The review provides an overview on approved pharmaceuticals like Gd-based CA and ^99mTc-based radiometal complexes, and also on novel agents such as ⁶⁸Ga-based PET tracers. Metal complexes are presented by their imaging modality, with subsections focusing on their structure and mode of action. Uptake mechanisms, metabolism, and specificity are presented, in context with advantages and limitations of the diagnostic application and taking into account the respective imaging technique.

Positron-emission tomography for hepatocellular carcinoma: Current status and future prospects

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer mortality worldwide. Various imaging modalities provide important information about HCC for its clinical management. Since positron-emission tomography (PET) or PET-computed tomography was introduced to the oncologic setting, it has played crucial roles in detecting, distinguishing, accurately staging, and evaluating local, residual, and recurrent HCC. PET imaging visualizes tissue metabolic information that is closely associated with treatment. Dynamic PET imaging and dual-tracer have emerged as complementary techniques that aid in various aspects of HCC diagnosis. The advent of new radiotracers and the development of immuno-PET and PET-magnetic resonance imaging have improved the ability to detect lesions and have made great progress in treatment surveillance. The current PET diagnostic capabilities for HCC and the supplementary techniques are reviewed herein.

Tumor Identification of Less Aggressive or Indolent Lymphoma With Whole-Body 11C-Acetate PET/CT

PURPOSE

The aim of this study was to investigate the diagnostic performance of whole-body [C]acetate PET/CT in less aggressive or indolent lymphomas, wherein [F]FDG PET/CT would exhibit limited sensitivity.

METHODS

Between September 2016 and May 2018, we prospectively evaluated 17 patients (9 men, 8 women; mean age [range], 71 [45-87] years) with pathologically proven less aggressive or indolent lymphomas according to Non-Hodgkin's Lymphoma Classification Project, using both [F]FDG PET/CT and [C]acetate PET/CT (performed on the same day). Detected nodal lesions were recorded according to the Ann Arbor classification. Extranodal (EN) lesions were also evaluated. We compared whole-body lesion detection between [F] FDG PET/CT and [C]acetate PET/CT using the McNemar test.

RESULTS

In all patients, significantly more nodal and EN lesions were detected using [C]acetate PET/CT than [F]FDG PET/CT (nodal: 84 vs 64 regions; P < 0.001; EN: 26 vs 19 regions, P = 0.039). Bone lesions were detected in 8 and 5 patients using [C]acetate PET/CT and [F]FDG PET/CT, respectively (P = 0.25). Among the 14 patients (82.4%) who underwent bone marrow biopsy, bone marrow involvement was detected with sensitivities of 100% (6/6 patients) and 80% (5/6 patients) using [C]acetate PET/CT and [F]FDG PET/CT, respectively. Multiple areas of focal uptake in the spleen of 1 patient were exhibited on [F]FDG PET/CT but not [C]acetate PET/CT.

CONCLUSIONS

[C]acetate PET/CT exhibited greater sensitivity than [F]FDG PET/CT for lesion detection in patients with less aggressive or indolent lymphomas, thus promising applicability as a physiological tracer in the study of such lesions.

Patterns of Discordance Between Pretransplant Imaging Stage of Hepatocellular Carcinoma and Posttransplant Pathologic Stage: A Contemporary Appraisal of the Milan Criteria

BACKGROUND

Patients with hepatocellular carcinoma (HCC) exceeding Milan criteria on explant pathology are at increased risk of recurrence and death. Discordance between contemporary magnetic resonance imaging (MRI) and explant pathology, and preoperative characteristics predictive of discordance are not well understood.

METHODS

Patients who underwent orthotopic liver transplantation for HCC after preoperative MRI were identified in a prospectively collected institutional database (January 2003 to December 2013). Patients were dichotomized to "within" or "outside" Milan criteria by both imaging and explant pathologic evaluation. Binary logistic regression and Kaplan-Meier methodology were used to identify independent predictors of imaging/pathologic discordance and its impact on posttransplant survival.

RESULTS

Of 318 patients with HCC meeting Milan criteria by MRI at the time of orthotopic liver transplantation, 248 (78.0%) remained within a pathological correlate of Milan criteria on explant examination. Understaging was associated with worse median recurrence-free survival (64.0 months vs 140.0 months, P = 0.002) and overall survival (96.0 months vs 143.0 months, P = 0.005), and did not vary between patients exceeding criteria due to tumor explant greater than 5 cm, more than 3 tumor foci, or a tumor greater than 3 cm in the setting of multifocality. Discordance was independently associated with an increasing serum alpha fetal protein level (odds ratio, 2.82; 95% confidence interval, 1.37-5.79; P = 0.005).

CONCLUSIONS

Underestimating HCC burden before liver transplant remains frequent despite contemporary imaging technologies. Patients with an increasing alpha fetal protein before transplantation may benefit from more frequent testing or novel neoadjuvant therapies.

Multidisciplinary approach for post-liver transplant recurrence of hepatocellular carcinoma: A proposed management algorithm

A large number of liver transplants have been performed for hepatocellular carcinoma (HCC), and recurrence is increasingly encountered. The recurrence of HCC after liver transplantation is notoriously difficult to manage. We hereby propose multi-disciplinary management with a systematic approach. The patient is jointly managed by the transplant surgeon, physician, oncologist and radiologist. Immunosuppressants should be tapered to the lowest effective dose to protect against rejection. The combination of a mammalian target of rapamycin inhibitor with a reduced calcineurin inhibitor could be considered with close monitoring of graft function and toxicity. Comprehensive staging can be performed by dual-tracer positron emission tomography-computed tomography or the combination of contrast computed tomography and a bone scan. In patients with disseminated recurrence, sorafenib confers survival benefits but is associated with significant drug toxicity. Oligo-recurrence encompasses recurrent disease that is limited in number and location so that loco-regional treatments convey disease control and survival benefits. Intra-hepatic recurrence can be managed with graft resection, but significant operative morbidity is expected. Radiofrequency ablation and stereotactic body radiation therapy (SBRT) are effective alternative strategies. In patients with more advanced hepatic disease, regional treatment with trans-arterial chemoembolization or intra-arterial Yttrium-90 can be considered. For patients with extra-hepatic oligo-recurrence, loco-regional treatment can be considered if practical. Patients with more than one site of recurrence are not always contraindicated for curative treatments. Surgical resection is effective for patients with pulmonary oligo-recurrence, but adequate lung function is a pre-requisite. SBRT is a non-invasive and effective modality that conveys local control to pulmonary and skeletal oligo-recurrences.

Role of pre-transplant 18F-FDG PET/CT in predicting hepatocellular carcinoma recurrence after liver transplantation

The last two decades have seen a paradigm shift in the selection of patients with hepatocellular carcinoma (HCC) for liver transplantation. Microvascular invasion and differentiation have been the most significant factors affecting post-transplant recurrence; however, because of inherent disadvantages of pre-transplant biopsy, histological criteria never gained popularity. Recently, the selection criteria evolved from morphological to biological criteria, such as biomarkers and response to loco-regional therapy. With the introduction of multimodality imaging, combination of computed tomography with nuclear medicine imaging, particularly, 18F-fluorodeoxyglucose positron emission tomography fulfilled an unmet need and rapidly became a critical component of HCC management. This review article will focus on the use of 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography in the pre-transplant evaluation of HCC patients with special discussion on its ability to predict HCC recurrence after liver transplantation.

PET/MRI for Gastrointestinal Imaging: Current Clinical Status and Future Prospects

Positron emission tomography (PET)/computed tomography (CT) with 2-deoxy-2-[¹⁸F]fluoro-d-glucose (FDG) has become the standard of care for the initial staging and subsequent treatment response assessment for numerous gastrointestinal malignancies. However, it is often supplemented by magnetic resonance imaging (MRI) for local tumor staging. Hybrid PET/MRI scanners, which acquire PET data and MRI data simultaneously, have the potential to provide accurate whole-body staging in a single examination. Furthermore, to address certain limitations of FDG, many new PET tracers have been developed to probe distinctive aspects of tumor biology.

Diagnostic and Prognostic Role of 18-FDG PET/CT in the Management of Resectable Biliary Tract Cancer

OBJECTIVES

Role of 18-FDG PET/CT had been well established in other more prevalent malignancies such as colorectal and lung cancer; however, this is not as well defined in cholangiocarcinoma. Literature focusing on the prognostic values of preoperative PET/CT for resectable cholangiocarcinoma is scarce.

METHOD

This is a retrospective cohort of 66 consecutive patients who had received curative resection for cholangiocarcinoma from 2010 to 2015. All patients had preoperative 18-FDG PET/CT performed. Accuracy of metastatic lymph node detection of PET/CT and the prognostic value of maximum standard uptake value (SUV-max) was explored.

RESULTS

There were 38 male and 28 female recruited, and the median age was 66. Intrahepatic cholangiocarcinoma (ICC) constituted the majority (59.1%) of the cases, followed by hilar cholangiocarcinoma (22.8%), gallbladder cancer (13.6%) and common bile duct cancer (4.5%). The 3-year disease-free survival (DFS) and overall survival (OS) of the whole population were 27.1 and 39.2%, respectively. The median follow-up duration was 27 months. The accuracy of PET/CT in metastatic lymph node detection was 72.7% (P = 0.005, 95% CI 0.583-0.871) and 81.8% (P = 0.011, 95% CI 0.635-0.990) in whole population and ICC subgroup analysis, respectively. SUV-max was shown by multivariate analysis to be an independent factor for DFS (P = 0.007 OR 1.16, 95% CI 1.04-1.29) and OS (P = 0.012 OR 1.145, 95% CI 1.030-1.273) after resection. SUV-max of 8 was shown to be a discriminant cut-off for poor oncological outcomes in patients with early cholangiocarcinoma (TNM stage I or II) after curative resection (3-year DFS: 21.2 vs. 63.2%, P = 0.004, and 3-year OS: 29 vs. 74% P = 0.048, respectively).

CONCLUSION

PET/CT is a reliable imaging modality for metastatic lymph node detection in cholangiocarcinoma. Tumour SUV-max is an independent factor for oncological outcomes in patients with resectable disease. For patients who have TNM stage I or II cholangiocarcinoma, tumour SUV-max over 8 is associated with significantly inferior disease-free and overall survival even after curative resection.

Hyperpolarized carbon-13 magnetic resonance spectroscopic imaging: a clinical tool for studying tumour metabolism

Glucose metabolism in tumours is reprogrammed away from oxidative metabolism, even in the presence of oxygen. Non-invasive imaging techniques can probe these alterations in cancer metabolism providing tools to detect tumours and their response to therapy. Although Positron Emission Tomography with (18F)2-fluoro-2-deoxy-D-glucose (18F-FDG PET) is an established clinical tool to probe cancer metabolism, it has poor spatial resolution and soft tissue contrast, utilizes ionizing radiation and only probes glucose uptake and phosphorylation and not further downstream metabolism. Magnetic Resonance Spectroscopy (MRS) has the capability to non-invasively detect and distinguish molecules within tissue but has low sensitivity and can only detect selected nuclei. Dynamic Nuclear Polarization (DNP) is a technique which greatly increases the signal-to-noise ratio (SNR) achieved with MR by significantly increasing nuclear spin polarization and this method has now been translated into human imaging. This review provides a brief overview of this process, also termed Hyperpolarized Carbon-13 Magnetic Resonance Spectroscopic Imaging (HP 13C-MRSI), its applications in preclinical imaging, an outline of the current human trials that are ongoing, as well as future potential applications in oncology.

Survival outcomes of liver transplantation for hepatocellular carcinoma in patients with normal, high and very high preoperative alpha-fetoprotein levels

AIM

To investigate the impact of alpha-fetoprotein (AFP) on long-term recurrence rate and overall survival and we also aimed to define the level of AFP leading to a higher risk of disease recurrence and affecting patient survival.

METHODS

Data of adult patients who received liver transplant (LT) for hepatocellular carcinoma (HCC) at our hospital from January 2000 to December 2013 were reviewed. Reviewed data included demographic characteristics, preoperative AFP level, operative details, follow-up details, and survival outcomes. Patients were mostly listed for LT based on Milan or UCSF criteria. For the purpose of this study, normal AFP level was defined as AFP value < 10 ng/mL, high AFP level was defined as AFP value ≥ 10 to < 400 ng/mL, and very high AFP level was defined as AFP ≥ 400 ng/mL. The patients were divided into these 3 groups accordingly. Survival rates were plotted as Kaplan-Meier curves and compared by log-rank analysis. Continuous variables were expressed as median (interquartile range). Categorical variables were compared by Spearman’s test. Discriminative analysis was used to define the lowest value of AFP that could affect the overall survival in study population. Statistical significance was defined by a P value of < 0.05.

RESULTS

Totally 250 adult patients underwent LT for HCC in the study period. Eight-four of them received deceased-donor LT and 166 had living-donor LT. The patients were divided into 3 groups: Group A, AFP < 10 ng/mL (n = 83); Group B, AFP ≥ 10 to < 400 ng/mL (n = 131); Group C, AFP ≥ 400 ng/mL (n = 36). The commonest etiology was hepatitis-B-related cirrhosis. The Model for End-stage Liver Disease scores in these groups were similar (median, 13 vs 13 vs 12; P = 0.745). The time to operation in Group A was longer (median, 94 vs 31 vs 35 d; P = 0.001). The groups were similar in hospital mortality (P = 0.626) and postoperative complication (P = 0.702). Pathology of explants showed that the 3 groups had similar numbers of tumor nodules, but the tumors in Group C were larger (A: 2.5 cm, B: 3.0 cm, C: 4.0 cm; P = 0.003). Group C had a bigger proportion of patients who were beyond Milan criteria (P = 0.010). Poor differentiation and vascular permeation were also more common in this group (P = 0.017 and P = 0.003 respectively). It also had poorer 5-year survival (A: 85.5%, B: 82.4%, C: 66%; P = 0.029). The 5-year disease-free survival was 84.3% in Group A, 80.1% in Group B, and 61.1% in Group C. Receiver operating characteristic area under the curve for AFP in predicting tumor recurrence was 0.685. The selected cut-off value was 54 ng/mL for AFP (C-index 0.685; 95%CI: 0.592-0.779; sensitivity 0.595; specificity 0.687). On discriminative analysis, AFP value of 105 ng/mL was shown to affect the overall survival of the patients.

CONCLUSION

HCC patients with a high preoperative AFP level had inferior survival after LT. AFP level of 54 ng/mL was associated with disease recurrence, and AFP level of 105 ng/mL was found to be the cut-off value for overall survival difference.

PET/MRI: Where might it replace PET/CT?

Simultaneous positron emission tomography and MRI (PET/MRI) is a technology that combines the anatomic and quantitative strengths of MR imaging with physiologic information obtained from PET. PET and computed tomography (PET/CT) performed in a single scanning session is an established technology already in widespread and accepted use worldwide. Given the higher cost and complexity of operating and interpreting the studies obtained on a PET/MRI system, there has been question as to which patients would benefit most from imaging with PET/MRI versus PET/CT. In this article, we compare PET/MRI with PET/CT, detail the applications for which PET/MRI has shown promise and discuss impediments to future adoption. It is our hope that future work will prove the benefit of PET/MRI to specific groups of patients, initially those in which PET/CT and MRI are already performed, leveraging simultaneity and allowing for greater degrees of multiparametric evaluation.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2017;46:1247-1262.

Utility of [18F]FSPG PET to Image Hepatocellular Carcinoma: First Clinical Evaluation in a US Population

PURPOSE

Non-invasive imaging is central to hepatocellular carcinoma (HCC) diagnosis; however, conventional modalities are limited by smaller tumors and other chronic diseases that are often present in patients with HCC, such as cirrhosis. This pilot study evaluated the feasibility of (4S)-4-(3-[¹⁸F]fluoropropyl)-L-glutamic acid ([¹⁸F]FSPG) positron emission tomography (PET)/X-ray computed tomography (CT) to image HCC. [¹⁸F]FSPG PET/CT was compared to standard-of-care (SOC) magnetic resonance imaging (MRI) and CT, and [¹¹C]acetate PET/CT, commonly used in this setting. We report the largest cohort of HCC patients imaged to date with [¹⁸F]FSPG PET/CT and present the first comparison to [¹¹C]acetate PET/CT and SOC imaging. This study represents the first in a US HCC population, which is distinguished by different underlying comorbidities than non-US populations.

PROCEDURES

x_C- transporter RNA and protein levels were evaluated in HCC and matched liver samples from The Cancer Genome Atlas (n = 16) and a tissue microarray (n = 83). Eleven HCC patients who underwent prior MRI or CT scans were imaged by [¹⁸F]FSPG PET/CT, with seven patients also imaged with [¹¹C]acetate PET/CT.

RESULTS

x_C- transporter RNA and protein levels were elevated in HCC samples compared to background liver. Over 50 % of low-grade HCCs and ~70 % of high-grade tumors exceeded background liver protein expression. [¹⁸F]FSPG PET/CT demonstrated a detection rate of 75 %. [¹⁸F]FSPG PET/CT also identified an HCC devoid of typical MRI enhancement pattern. Patients scanned with [¹⁸F]FSPG and [¹¹C]acetate PET/CT exhibited a 90 and 70 % detection rate, respectively. In dually positive tumors, [¹⁸F]FSPG accumulation consistently resulted in significantly greater tumor-to-liver background ratios compared with [¹¹C]acetate PET/CT.

CONCLUSIONS

[¹⁸F]FSPG PET/CT is a promising modality for HCC imaging, and larger studies are warranted to examine [¹⁸F]FSPG PET/CT impact on diagnosis and management of HCC. [¹⁸F]FSPG PET/CT may also be useful for phenotyping HCC tumor metabolism as part of precision cancer medicine.

18F-FDG-PET for Assessing Biological Viability and Prognosis in Liver Transplant Patients with Hepatocellular Carcinoma

Liver transplantation (LT) has become standard of care in patients with non-resectable early stage hepatocellular carcinoma (HCC) in liver cirrhosis. Currently, patient selection for LT is strictly based on tumor size and number, provided by the Milan criteria. This may, however, exclude patients with advanced tumor load but favourable biology from a possibly curative treatment option. It became clear in recent years that biological tumor viability rather than tumor macromorphology determines posttransplant outcome. In particular, microvascular invasion and poor grading reflect tumor aggressiveness and promote the risk of tumor relapse. Pretransplant biopsy is not applicable due to tumor heterogeneity and risk of tumor cell seeding. ¹⁸F-fludeoxyglucose (¹⁸F-FDG) positron emission tomography (PET), an established nuclear imaging device in oncology, was demonstrated to non-invasively correlate with unfavorable histopathologic features. Currently, there is an increasing amount of evidence that ¹⁸F-FDG-PET is very useful for identifying eligible liver transplant patients with HCC beyond standard criteria but less aggressive tumor properties. In order to safely expand the HCC selection criteria and the pool of eligible liver recipients, tumor evaluation with ¹⁸F-FDG-PET should be implemented in pretransplant decision process.

Refining prognosis in patients with hepatocellular carcinoma through incorporation of metabolic imaging biomarkers

PURPOSE

18F-fluorodeoxyglucose positron emission tomopraphy/computed tomography (FDGPET/CT) has been proven to be useful for imaging many types of cancer; however, its role is not well defined in hepatocellular carcinoma (HCC). We assessed the prognostic value of metabolic imaging biomarkers as established by baseline pretreatment FDG PET/CT in patients with HCC.

METHODS

We retrospectively analyzed the records of patients with HCC who underwent FDG PET/CT before initial treatment from May 2013 through May 2014. Four PET/CT parameters were measured: maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), metabolic tumor volume (MTV), and tumor-to-normal-liver SUV ratio (TNR). Optimal cut-off values for the PET/CT parameters to stratify patients in terms of overall survival (OS) were determined. Multivariate analysis was performed to determine whether the PET/CT parameters could add to the prognostic value of the Cancer of the Liver Italian Program (CLIP) scoring system and the Barcelona-Clinic Liver Cancer (BCLC) staging system.

RESULTS

The analysis included 56 patients. Univariate analysis of the association between OS and continuous variables, including the PET/CT parameters SUVmax, TLG, tumor size, total bilirubin level, and alkaline phosphatase level were significant predictors of OS. SUVmax ≥ 11.7, TLG ≥ 1,341, MTV ≥ 230 mL, and TNR ≥ 4.8 were identified as cut-off values. Multivariate analysis revealed that SUVmax ≥ 11.7 and TNR ≥ 4.8 were independent factors predicting a poor prognosis in both the CLIP scoring system and the BCLC staging system, as was TLG in the BCLC staging system.

CONCLUSION

Pretreatment FDG PET/CT in patients with HCC can add to the prognostic value of standard clinical measures. Incorporation of imaging biomarkers derived from FDG PET/CT into HCC staging systems should be considered.

Pure Laparoscopic Hepatectomy Versus Open Hepatectomy for Hepatocellular Carcinoma in 110 Patients With Liver Cirrhosis: A Propensity Analysis at a Single Center

OBJECTIVE

To investigate the long-term outcomes of pure laparoscopic hepatectomy versus open hepatectomy for hepatocellular carcinoma (HCC) with background cirrhosis.

BACKGROUND

Laparoscopic hepatectomy has been gaining popularity, but has not been widely accepted, because published data were gathered from small numbers of patients.

METHODS

Data of patients diagnosed with HCC and cirrhosis treated by hepatectomy were reviewed. The outcomes of pure laparoscopic hepatectomy were compared with those of open hepatectomy. Propensity score matching of patients in a ratio of 1:3 was conducted.

RESULTS

There were 110 patients and 330 patients in the laparoscopic group and the open group, respectively. The laparoscopic group had less blood loss (150 vs 400 mL; P < 0.001), shorter operation time (185 vs 255 minutes; P < 0.001), and shorter hospital stay (4vs 7 days; P < 0.001). The median overall survival was 136 months in the laparoscopic group and 120 months in the open group. The 1, 3, and 5-year overall survival rates were 98.9%, 89.8%, and 83.7%, respectively, in the laparoscopic group, and 94%, 79.3%, and 67.4%, respectively, in the open group (P = 0.033). The median disease-free survival was 66.37 months in the laparoscopic group and 52.4 months in the open group. The 1, 3, and 5-year disease-free survival rates were 87.7%, 65.8%, and 52.2%, respectively, in the laparoscopic group, and 75.2%, 56.3%, and 47.9%, respectively, in the open group (P = 0.141).

CONCLUSIONS

Pure laparoscopic hepatectomy for HCC can be carried out safely with favorable short-term and long-term outcomes even in cirrhotic patients at high-volume liver cancer centers.

Controversies and evidence of hepatic resection for hepatocellular carcinoma

Symptoms of early hepatocellular carcinoma (HCC) often go unnoticed, so more than half of patients with primary HCC are diagnosed after their disease has already reached an intermediate or advanced stage, or after portal hypertension has appeared. While hepatic resection is widely recognized as a first-line therapy to treat very early or early HCC, its use in treating intermediate or advanced HCC or HCC involving portal hypertension remains controversial. Here we review PubMed-indexed literature covering the use of hepatic resection for such patients. The available evidence strongly suggests that, as a result of improvements in surgical techniques and perioperative care, hepatic resection can benefit many patients with intermediate or advanced HCC or with HCC associated with portal hypertension.

Role of positron emission tomography/computed tomography in living donor liver transplantation for hepatocellular carcinoma

Living donor liver transplantation (LDLT) becomes an important option for treatment for patients with hepatocellular carcinoma (HCC). With the advance of imaging modalities such as computed tomography (CT) and magnetic resonance image (MRI), preoperative staging and diagnosis for HCC was improved in LDLT. However, morphological characteristics based on the tumor number and size do not represent the tumor pathology and prognosis clearly. Therefore, many criteria using various markers have been reported, but still have limitation to predict the pathology and prognosis. Recently, 18F-fluorodeoxyglucose-positron emission tomography/CT (18F-FDG PET/CT) was introduced to have the usefulness for detection of extrahepatic metastases and prediction of post-transplant prognosis in liver transplantation (LT). Furthermore, the hybrid concept with both biologic activity using PET/CT and morphologic tumor characteristics using CT and MRI was reported to be selection criteria for the patient with HCC waiting LDLT. We will discuss the role of 18F-FDG PET/CT in LDLT as various aspects including tumor detection, pathology prediction, prognosis prediction, and possibility of selecting criteria.

Pure Laparoscopic Versus Open Left Lateral Sectionectomy for Hepatocellular Carcinoma: A Single-Center Experience

INTRODUCTION

Laparoscopic left lateral sectionectomy has been proven to be a safe and effective treatment for liver lesions. However, most of the literatures only reported this treatment method on benign lesion or colorectal metastases. The data on long-term outcome of laparoscopic left lateral section resection in patients with HCC and cirrhosis are still limited. The aim of this study is to analyze the survival outcome of laparoscopic left lateral sectionectomy when compared to open approach in patients with HCCs.

METHOD

Between January 2004 and September 2014, 967 patients had primary HCC with hepatectomy performed. Twenty-four patients had undergone pure laparoscopic left lateral sectionectomy for hepatocellular carcinoma (HCC). Twenty-nine patients with case-matched tumor characteristics and liver functions but received open left lateral sectionectomy for HCC were included for comparison.

RESULTS

Comparing laparoscopic group to open resection group, the median operation time was 190.5 versus 195 min (P = 0.734); the median blood loss was 100 versus 300 ml (P < 0.001). Hospital stay was 5 days in laparoscopic group versus 6 days in the open group (P = 0.057). There was no difference between the two groups in terms of complications (P = 0.495). The median survival in laparoscopic group was >115 months versus >125 months in the open group (P = 0.853).

CONCLUSION

Laparoscopic left lateral sectionectomy for HCC is a safe and simple procedure associated with less blood loss. The survival outcome is comparable with conventional open approach. It is becoming a more favorable treatment option even for patients with HCC and cirrhosis.

Metabolic Imaging to Assess Treatment Response to Cytotoxic and Cytostatic Agents

For several decades, cytotoxic chemotherapeutic agents were considered the basis of anticancer treatment for patients with metastatic tumors. A decrease in tumor burden, assessed by volumetric computed tomography and magnetic resonance imaging, according to the response evaluation criteria in solid tumors (RECIST), was considered as a radiological response to cytotoxic chemotherapies. In addition to RECIST-based dimensional measurements, a metabolic response to cytotoxic drugs can be assessed by positron emission tomography (PET) using (18)F-fluoro-thymidine (FLT) as a radioactive tracer for drug-disrupted DNA synthesis. The decreased (18)FLT-PET uptake is often seen concurrently with increased apparent diffusion coefficients by diffusion-weighted imaging due to chemotherapy-induced changes in tumor cellularity. Recently, the discovery of molecular origins of tumorogenesis led to the introduction of novel signal transduction inhibitors (STIs). STIs are targeted cytostatic agents; their effect is based on a specific biological inhibition with no immediate cell death. As such, tumor size is not anymore a sensitive end point for a treatment response to STIs; novel physiological imaging end points are desirable. For receptor tyrosine kinase inhibitors as well as modulators of the downstream signaling pathways, an almost immediate inhibition in glycolytic activity (the Warburg effect) and phospholipid turnover (the Kennedy pathway) has been seen by metabolic imaging in the first 24 h of treatment. The quantitative imaging end points by magnetic resonance spectroscopy and metabolic PET (including 18F-fluoro-deoxy-glucose, FDG, and total choline) provide an early treatment response to targeted STIs, before a reduction in tumor burden can be seen.

Biphenotypic hepatic tumors: imaging findings and review of literature

PURPOSE

To describe imaging findings in biphenotypic hepatic tumors (BPT) and a proposal for new imaging classification based on contrast-enhanced imaging.

METHODS

Retrospective review of CT, MRI, PET/CT, and ultrasound findings in 39 patients with histologically confirmed BPT was performed. Tumor markers including AFP, L3 fraction, CA 19.9, CA 125, and CEA were recorded. Based on the dynamic enhancement features, BPT were categorized into 4 enhancement patterns (Types 1-4). Enhancement patterns were correlated with other imaging findings and tumor markers. Imaging features and tumor markers that were not consistent with diagnosis of hepatocellular carcinoma or intrahepatic cholangiocarcinoma based on enhancement pattern were considered discordant findings.

RESULTS

Enhancement patterns in 29 patients (CT/MR) included 23 Type 2 (continuous peripheral rim of late arterial hyperenhancement with washout or fade in portal venous and/or delayed phases, ±delayed central enhancement) and 2 of each Types 1, 2, and 3. Discordant imaging findings were present in two patients with Type 2 pattern and in one patient with Type 1 pattern. Both AFP and CA 19.9 were elevated in 15 of 33 of patients. Tumor markers AFP and CA 19.9 were discordant in 17 of 21 patients with Type 2 pattern, two of two patients with Type 3 pattern. Most BPTs were markedly PET avid with average SUV max of 8.2. Most frequent ultrasound appearance is peripheral hypoechogenicity and central hyperechogenicity.

CONCLUSIONS

BPT most commonly present with imaging features similar to cholangiocarcinoma or metastases. BPT can be suggested when imaging findings or tumor markers are discordant with the most likely diagnosis based on enhancement pattern.

Does hepatitis B seroconversion affect survival outcome in patients with hepatitis B related hepatocellular carcinoma?

BACKGROUND

Little is known about whether hepatitis B surface antigen (HBsAg) seroconversion (SC) contributes to any survival benefits for patients with hepatocellular carcinoma (HCC).

METHODS

All patients with hepatitis B-related HCC and HBsAg seroclearance between 1989 and 2013 were identified. Case- and control-groups were matched according to their stage of disease and mode of treatment. Baseline demographics, liver function, and overall survivals (OS) were compared between these two groups.

RESULTS

Thirty-nine HCC cases with HBsAg SC were identified, and 312 non-seroconversion (NSC) HCC cases were matched. Forty-eight percent of patients had curative resections, 14% were treated with ablation and 38% were for palliation. Age of patients in SC group was older than those in NSC group (P=0.026). Although there was significantly better liver function in SC vs. NSC groups in terms of bilirubin (P=0.027), albumin (P=0.003), AST (P=0.001) and ALT (P<0.001), there was no overall difference in Child-Pugh grade among the two groups. In regarding tumour pathology, SC commonly presented with solitary tumour nodule as compared to multiple nodules in NSC (P=0.027), and was also frequently associated with a normal background liver parenchyma (P<0.001). Although no survival benefit was confirmed in log-rank analysis between SC and NSC, the absolute 5-year survival of SC group was better in resection (72.2% vs. 55.3%), ablation (83.3% vs. 57.4%) and palliation (24.4% vs. 14.4%).

CONCLUSIONS

HCC patients with HBsAg SC are associated with a better background liver parenchyma and function, and might contribute to an improved long-term survival.