Predictive Value of 18F-FDG PET/CT for Vascular Invasion in Patients With Hepatocellular Carcinoma Before Liver Transplantation. Clin Nucl Med. 2017;42:e183-e187. [PMID: 28114226 DOI: 10.1097/rlu.0000000000001545]

Correlation between 18F-FDG PET/CT metabolic parameters and microvascular invasion before liver transplantation in patients with hepatocellular carcinoma

BACKGROUND

Microvascular infiltration (MVI) before liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) is associated with postoperative tumor recurrence and survival. MVI is mainly assessed by pathological analysis of tissue samples, which is invasive and heterogeneous. PET/computed tomography (PET/CT) with 18F-labeled fluorodeoxyglucose (18F-FDG) as a tracer has been widely used in the examination of malignant tumors. This study investigated the association between 18F-FDG PET/CT metabolic parameters and MVI before LT in HCC patients.

METHODS

About 124 HCC patients who had 18F-FDG PET/CT examination before LT were included. The patients' clinicopathological features and 18F-FDG PET/CT metabolic parameters were recorded. Correlations between clinicopathological features, 18F-FDG PET/CT metabolic parameters, and MVI were analyzed. ROC curve was used to determine the optimal diagnostic cutoff value, area under the curve (AUC), sensitivity, and specificity for predictors of MVI.

RESULT

In total 72 (58.06%) patients were detected with MVI among the 124 HCC patients. Univariate analysis showed that tumor size (P = 0.001), T stage (P < 0.001), maximum standardized uptake value (SUVmax) (P < 0.001), minimum standardized uptake value (SUVmin) (P = 0.031), mean standardized uptake value (SUVmean) (P = 0.001), peak standardized uptake value (SUVpeak) (P = 0.001), tumor-to-liver ratio (SUVratio) (P = 0.010), total lesion glycolysis (TLG) (P = 0.006), metabolic tumor volume (MTV) (P = 0.011) and MVI were significantly different. Multivariate logistic regression showed that tumor size (P = 0.018), T stage (P = 0.017), TLG (P = 0.023), and MTV (P = 0.015) were independent predictors of MVI. In the receiver operating characteristic curve, TLG predicted MVI with an AUC value of 0.645. MTV predicted MVI with an AUC value of 0.635. Patients with tumor size ≥5 cm, T3-4, TLG > 400.67, and MTV > 80.58 had a higher incidence of MVI.

CONCLUSION

18F-FDG PET/CT metabolic parameters correlate with MVI and may be used as a noninvasive technique to predict MVI before LT in HCC patients.

18F-fluorodeoxyglucose positron emission tomography/computed tomography parameters are associated with histological outcomes in superficial esophageal squamous cell carcinoma

Endoscopic submucosal dissection is a standard treatment for early esophageal squamous cell carcinoma. However, submucosal or lymphovascular invasion increases the risk of lymph node metastasis. Although 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) parameters are associated with prognosis in patients with advanced esophageal squamous cell carcinoma, the utility of FDG PET/CT in diagnosing superficial esophageal carcinoma remains unclear. This study aimed to investigate the association between FDG PET/CT parameters and histopathological findings in superficial esophageal carcinoma. Fifty-three patients with superficial esophageal cancer who underwent FDG PET/CT scans before undergoing interventions were retrospectively analyzed. The maximal standardized uptake value (SUVmax), metabolic tumor volume, and total lesion glycolysis were significantly higher in the cases with submucosal invasion (T1b) compared with those confined to the muscularis mucosa (T1a). In contrast, classification of intrapapillary capillary loops patterns with magnifying endoscopy did not yield statistical differences between T1a and T1b. Multivariable analysis revealed that SUVmax was the only independent predictor of submucosal and lymphovascular invasion. This study demonstrated that SUVmax may be useful in predicting submucosal and lymphovascular invasion. Thus, the value of SUVmax may guide clinical decision-making in superficial esophageal squamous cell carcinoma.

Predictive Value of Preoperative 18 Fludeoxyglucose Positron Emission Tomography-Computed Tomography for Survival in Liver Transplantation Due to Hepatocellular Cancer

BACKGROUND

We aimed to study the predictive value of preoperative perform [18F] Fludeoxyglucose positron emission tomography-computed tomography ([18] FDG PET-CT) for survival in liver transplantation due to hepatocellular cancer.

METHODS

Ninety-six patients who underwent liver transplantation for hepatocellular cancer (HCC) after preoperative PET-CT evaluation were examined for the study. All patients' ages, genders, body mass index, blood groups, Child-Pugh and Model for End-Stage Liver Disease scores, etiologies, median Alpha Fetoprotein values, Milan Criteria and T stages, grades, macrovascular and microvascular invasions, multicentricities, maximum and total tumor sizes, tumor number findings in explant specimens, and recurrence rates were analyzed statistically.

RESULTS

Statistically, microvascular (P = .002) and macrovascular invasions (P = .034) were observed more frequently in patients who are PET-CT (+) compared with patients who are PET-CT (-). PET-CT positivity was associated with shortened disease-free survival (DFS) statistically (P = .004).

CONCLUSION

Positron emission tomography-CT positivity may be important for predicting prognostic markers such as DFS and vascular invasion in the preoperative evaluation. Before transplantation, PET-CT should be applied to all patients with HCC.

Additional value of interleukin-6 level to predict histopathological features of hepatocellular carcinoma before liver transplantation

BACKGROUND & AIMS

Inflammatory biomarkers are increasingly used as outcome predictors in the field of oncology and liver transplantation for HCC, but no study has shown the prognostic value of IL6 after LT. The goal of this study was to evaluate the predictive value of IL-6 on histopathological features of HCC on explant, its predictive value on recurrence risk and its additional value to other scores and inflammatory markers at the time of transplantation.

METHODS

From 2009 to 2019, all adults transplanted with a first liver graft and diagnosed with HCC on the explant analysis were retrospectively included (n = 229). Only patients who had a pre-LT IL6 level determination were analysed in this study (n = 204).

RESULTS

High IL-6 level at transplantation was associated with a significantly higher risk of vascular invasion (15% vs 6%; p = 0.023), microsatellitosis (11% vs 3%; p = 0.013), lower rate of histological response both in terms of complete response (2% vs 14%, p = 0.004) and of necrosis (p = 0.010). Patients with pre-LT IL-6 level > 15 ng/ml had a lower overall and cancer-specific survival (p = 0.013). Recurrence-free survival was lower in patients with IL-6 > 15 ng/ml with a 3-year recurrence-free survival of 88% versus 78% (p = 0.034). IL6 levels were significantly higher in patients with early recurrence compared to patients without (p = 0.002) or with late recurrence (p = 0.044).

CONCLUSIONS

IL6 level at transplantation is an independent predictor of pejorative histological features of HCC and is associated to the risk of recurrence.

Achievement of Complete Response and Drug-Free Status by Atezolizumab plus Bevacizumab Combined with or without Curative Conversion in Patients with Transarterial Chemoembolization-Unsuitable, Intermediate-Stage Hepatocellular Carcinoma: A Multicenter Proof-Of-Concept Study

Introduction

Atezolizumab plus bevacizumab therapy is extremely effective in the treatment of intermediate-stage hepatocellular carcinoma (HCC), with a response rate of 44%, as reported in the IMbrave150 trial. When tumor shrinkage is obtained, achieving complete response (CR) is possible in many cases using curative conversion with resection, ablation, or superselective transarterial chemoembolization (TACE) with curative intent. This concept, i.e., curative conversion by combining systemic therapy and locoregional therapy, has not been reported before. This multicenter proof-of-concept study was conducted to show the value of curative conversion in immunotherapy-treated intermediate-stage HCC meeting TACE-unsuitable criteria.

Methods

This study included 110 consecutive Child-Pugh A patients who received atezolizumab plus bevacizumab as first-line treatment for unresectable and TACE-unsuitable intermediate-stage HCC at seven centers in Japan. CR rate, drug-free rate, time to CR, change in liver function, efficacy in positron emission tomography (PET)-positive HCC, progression-free survival (PFS), and overall survival (OS) were assessed in patients who achieved CR using resection, ablation, superselective TACE with curative intent following atezolizumab plus bevacizumab or atezolizumab plus bevacizumab alone.

Results

Clinical or pathological CR was achieved in 38 patients (35%) (median observation period: 21.2 months). The modalities of curative conversion in 35 patients were as follows: resection, 7; ablation, 13; and superselective TACE, 15. Three patients achieved clinical CR with atezolizumab plus bevacizumab therapy alone. Among the 38 CR patients, 25 achieved drug-free status. PFS was not reached, and 3 patients experienced recurrence after reaching CR. Regarding OS, there were no deaths in any of the CR patients. The albumin-bilirubin score did not deteriorate after locoregional therapy or resection. Of seven PET-positive patients who achieved CR with atezolizumab plus bevacizumab followed by curative conversion, five achieved drug-free status.

Conclusion

The achievement of CR rate by curative conversion in patients treated with atezolizumab plus bevacizumab as the preceding therapy for unresectable and TACE-unsuitable intermediate-stage HCC was 35%. Overall, 23% of patients achieved drug-free status and no recurrence was observed from this patient subgroup with CR and drug-free status. Thus, achieving CR and/or drug-free status should be a therapeutic goal for patients with intermediate-stage HCC without vascular invasion or extrahepatic spread.

Tumor to liver maximum standardized uptake value ratio of FDG-PET/CT parameters predicts tumor treatment response and survival of stage III non-small cell lung cancer

BACKGROUND

To assess the predictive values of primary tumor FDG uptake for patients with inoperable stage III non-small cell lung cancer (NSCLC) after concurrent chemoradiotherapy (CCRT).

METHODS

A total of 107 patients with diagnosis of stage III NSCLC and CCRT were enrolled. The tumor maximum uptake value (SUVmax) was standardized by calculating several ratios between tumor and each background tissues. The receiver operating characteristics curve (ROC) was used to compare the predictive power of prognostic models. The tumor objective response rate (ORR) and overall survival (OS) were compared and analyzed by the Kaplan-Meier method and univariate and multivariate Cox regression models.

RESULTS

The areas under ROC curve (AUCs) ranged from 0.72 to 0.81 among these tumor SUVmax and standardized SUVmax ratios, and the tumor SUVmax and tumor SUVmax-to-liver SUVmean ratio (TLMR) were more predictive of ORR (AUC, 0.81; 95% CI, 0.73-0.88 for tumor SUVmax and AUC, 0.84; 95%CI, 0.76-0.91 for TLMR) than any of other SUVmax ratios. The patients with lower tumor SUVmax, SUVmean and SUVmax ratios had a significantly better OS than those with their corresponding higher ones. Moreover, both univariate and multivariable analyses revealed that TLMR was significantly associated with better ORR and OS after adjustment with other prognostic variables.

CONCLUSIONS

TLMR, a standardized tumor SUVmax, was an independent prognostic predictor for tumor ORR and OS of patients with stage III NSCLC after CCRT.

Evaluating treatment response following locoregional therapy for hepatocellular carcinoma: A review of the available serological and radiological tools for assessment

Hepatocellular carcinoma (HCC) is an aggressive primary malignancy of the liver and is the third most common cause of cancer-related global mortality. There has been a steady increase in treatment options for HCC in recent years, including innovations in both curative and non-curative therapies. These advances have brought new challenges and necessary improvements in strategies of disease monitoring, to allow early detection of HCC recurrence. Current serological and radiological strategies for post-treatment monitoring and prognostication and their limitations will be discussed and evaluated in this review.

PET imaging of hepatocellular carcinoma by targeting tumor-associated endothelium using [68Ga]Ga-PSMA-617

OBJECTIVE

Hepatocellular carcinoma (HCC) is a malignant tumor associated with high morbidity and mortality rates. In many non-prostate solid tumors such as HCC, prostate-specific membrane antigens (PSMA) are overexpressed in tumor-associated endothelial cells. Therefore, the aim of this study was to evaluate the performance of [68Ga]Ga-PSMA-617 PET imaging on HCC with different animal models, including cell line-derived xenografts (CDX) and patient-derived xenografts (PDX), and to explore its mechanisms of function.

METHODS

[68Ga]Ga-PSMA-617 was prepared. The expression level of PSMA in two human hepatocellular cancer cells (HepG2 and HuH-7) was evaluated, and the cellular uptakes of [68Ga]Ga-PSMA-617 were assayed. HepG2 and HuH-7 subcutaneous xenograft models, HepG2 orthotopic xenograft models, and four different groups of PDX models were prepared. Preclinical pharmacokinetics and performance of [68Ga]Ga-PSMA-617 were evaluated in different types of HCC xenografts models using small animal PET and biodistribution studies.

RESULTS

Low PSMA expression level of HepG2 and HuH-7 cells was observed, and the cellular uptake and blocking study confirmed the non-specificity of the PSMA-targeted probe binding to HepG2 and HuH-7 cells. In the subcutaneous xenograft models, the tumor uptakes at 0.5 h were 0.76 ± 0.12%ID/g (HepG2 tumors) and 0.78 ± 0.08%ID/g (HuH-7 tumors), respectively, which were significantly higher than those of the blocking groups (0.23 ± 0.04%ID/g and 0.20 ± 0.04%ID/g, respectively). In the orthotopic xenograft models, PET images clearly displayed the tumor locations based on the preferential accumulation of [68Ga]Ga-PSMA-617 in tumor tissue versus normal liver tissue, suggesting the possibility of using [68Ga]Ga-PSMA-617 PET imaging to detect primary HCC lesions in deep tissue. In the four different groups of HCC PDX models, PET imaging with [68Ga]Ga-PSMA-617 provided clear tumor uptakes with prominent tumor-to-background contrast, further demonstrating its potential for the clinical imaging of PSMA-positive HCC lesions. The staining of tumor tissue sections with CD31- and PSMA-specific antibodies visualized the tumor-associated blood vessels and PSMA expression on endothelial cells in subcutaneous, orthotopic tissues, and PDX tissues, confirming the imaging with [68Ga]Ga-PSMA-617 might be mediated by targeting tumor associated endothelium.

CONCLUSION

In this study, in vivo PET on different types of HCC xenograft models illustrated high uptake within tumors, which confirmed that [68Ga]Ga-PSMA-617 PET may be a promising imaging modality for HCC by targeting tumor associated endothelium.

Role of preoperative prediction of microvascular invasion in hepatocellular carcinoma based on the texture of FDG PET image: A comparison of quantitative metabolic parameters and MRI

Objective: To investigate the role of prediction microvascular invasion (mVI) in hepatocellular carcinoma (HCC) by ¹⁸F-FDG PET image texture analysis and hybrid criteria combining PET/CT and multi-parameter MRI.

Materials and methods: Ninety-seven patients with HCC who received the examinations of MRI and ¹⁸F-FDG PET/CT were retrospectively included in this study and were randomized into training and testing cohorts. The lesion image texture features of ¹⁸F-FDG PET were extracted using MaZda software. The optimal predictive texture features of mVI were selected, and the classification procedure was conducted. The predictive performance of mVI by radiomics classier in training and testing cohorts was respectively recorded. Next, the hybrid model was developed by integrating the ¹⁸F-FDG PET image texture, metabolic parameters, and MRI parameters to predict mVI through logistic regression. Furthermore, the diagnostic performance of each time was recorded.

Results: The ¹⁸F-FDG PET image radiomics classier showed good predicted performance in both training and testing cohorts to discriminate HCC with/without mVI, with an AUC of 0.917 (95% CI: 0.824–0.970) and 0.771 (95% CI: 0.578, 0.905). The hybrid model, which combines radiomics classier, SUVmax, ADC, hypovascular arterial phase enhancement pattern on contrast-enhanced MRI, and non-smooth tumor margin, also yielded better predictive performance with an AUC of 0.996 (95% CI: 0.939, 1.000) and 0.953 (95% CI: 0.883, 1.000). The differences in AUCs between radiomics classier and hybrid classier were significant in both training and testing cohorts (DeLong test, both p < 0.05).

Conclusion: The radiomics classier based on ¹⁸F-FDG PET image texture and the hybrid classier incorporating ¹⁸F-FDG PET/CT and MRI yielded good predictive performance, which might provide a precise prediction of HCC mVI preoperatively.

PET-Based Radiogenomics Supports mTOR Pathway Targeting for Hepatocellular Carcinoma

PURPOSE

This work aimed to explore in depth the genomic and molecular underpinnings of hepatocellular carcinoma (HCC) with increased 2[18F]fluoro-2-deoxy-d-glucose (FDG) uptake in PET and to identify therapeutic targets based on this imaging-genomic surrogate.

EXPERIMENTAL DESIGN

We used RNA sequencing and whole-exome sequencing data obtained from 117 patients with HCC who underwent hepatic resection with preoperative FDG-PET/CT imaging as a discovery cohort. The primary radiogenomic results were validated with transcriptomes from a second cohort of 81 patients with more advanced tumors. All patients were allocated to an FDG-avid or FDG-non-avid group according to the PET findings. We also screened potential drug candidates targeting FDG-avid HCCs in vitro and in vivo.

RESULTS

High FDG avidity conferred worse recurrence-free survival after HCC resection. Whole transcriptome analysis revealed upregulation of mTOR pathway signals in the FDG-avid tumors, together with higher abundance of associated mutations. These clinical and genomic findings were replicated in the validation set. A molecular signature of FDG-avid HCCs identified in the discovery set consistently predicted poor prognoses in the public-access datasets of two cohorts. Treatment with an mTOR inhibitor resulted in decreased FDG uptake followed by effective tumor control in both the hyperglycolytic HCC cell lines and xenograft mouse models.

CONCLUSIONS

Our PET-based radiogenomic analysis indicates that mTOR pathway genes are markedly activated and altered in HCCs with high FDG retention. This nuclear imaging biomarker may stimulate umbrella trials and tailored treatments in precision care of patients with HCC.

Radiomics in Gastric Cancer: First Clinical Investigation to Predict Lymph Vascular Invasion and Survival Outcome Using 18F-FDG PET/CT Images

Background

Lymph vascular invasion (LVI) is an unfavorable prognostic indicator in gastric cancer (GC). However, there are no reliable clinical techniques for preoperative predictions of LVI. The aim of this study was to develop and validate PET/CT-based radiomics signatures for predicting LVI of GC preoperatively. Radiomics nomograms were also established to predict patient survival outcomes.

Methods

This retrospective study registered 148 GC patients with histopathological confirmation for LVI status, who underwent pre-operative PET/CT scans (Discovery VCT 64 PET/CT system) from December 2014 to June 2019. Clinic-pathological factors (age, gender, and tumor grade, etc.) and metabolic PET data (maximum and mean standardized uptake value, total lesion glycolysis and metabolic tumor volume) were analyzed to identify independent LVI predictors. The dataset was randomly assigned to either the training set or test set in a 7:3 ratios. Three-dimensional (3D) radiomics features were extracted from each PET- and CT-volume of interests (VOI) singularly, and then a radiomics signature (RS) associated with LVI status is built by feature selection. Four models with different modalities (PET-RS: only PET radiomics features; CT-RS: only CT radiomics features; PET/CT-RS: both PET and CT radiomics features; PET/CT-RS plus clinical data) were developed to predict LVI. Patients were postoperatively followed up with PET/CT every 6-12 months for the first two years and then annually up to five years after surgery. The PET/CT radiomics score (Rad-scores) was calculated to assess survival outcome, and corresponding nomograms with radiomics (NWR) or without radiomics (NWOR) were established.

Results

Tumor grade and maximum standardized uptake value (SUVmax) were the independent LVI predictor. 1037 CT and PET 3D radiomics features were extracted separately and reduced to 4 and 5 features to build CT-RS and PET-RS, respectively. PET/CT-RS and PET/CT-RS plus clinical data (tumor grade and SUVmax) were also developed. The ROC analysis demonstrated clinical usefulness of PET/CT-RS plus clinical data (AUC values for training and validation, respectively 0.936 and 0.914) and PET/CT-RS (AUC values for training and validation, respectively 0.881 and 0.854), which both are superior to CT-RS (0.838 and 0.824) and PET-RS (0.821 and 0.812). SUVmax and LVI were independent prognostic indicators of both OS and PFS. Decision curve analysis (DCA) demonstrated NWR outperformed NWOR and was established to assess survival outcomes. For estimation of OS and PFS, the C-indexes of the NWR were 0. 88 and 0.88 in the training set, respectively, while the C-indexes of the NWOR were 0. 82 and 0.85 in the training set, respectively.

Conclusions

The PET/CT-based radiomics analysis might serve as a non-invasive approach to predict LVI status in GC patients and provide effective predictors of patient survival outcomes.

[Small hepatocellular carcinoma : Diagnostics according to guidelines and established in the clinical setting]

CLINICAL/METHODICAL ISSUE

The diagnosis of hepatocellular carcinoma (HCC)-especially the characterization of small lesions <2 cm-continues to be a radiological challenge.

STANDARD RADIOLOGICAL METHODS

In the current S3 guideline on diagnosis and therapy of HCC, contrast-enhanced imaging examinations, such as contrast-enhanced ultrasonography (CEUS), computed tomography (CT), and magnetic resonance imaging (MRI), are still the diagnostic standard.

METHODOLOGICAL INNOVATIONS

HCC in the cirrhotic liver should be diagnosed by its typical contrast-enhanced pattern in the MRI. In addition, the use of quality assurance instruments such as LI-RADS (Liver Imaging Reporting and Data System) contributes to the desired consistency of findings, even with small ambiguous findings.

PERFORMANCE

Many studies have shown that the LI-RADS classification reflects the likelihood of HCC and other malignant liver lesions.

ACHIEVEMENTS

Guidelines and quality assurance instruments contribute to a more precise diagnosis in patients with suspected HCC.

PRACTICAL RECOMMENDATIONS

A guideline-compliant diagnostic algorithm and the LI-RADS should be used across the board for accurate HCC diagnostics.

Liver Transplantation for Hepatocellular Carcinoma: How Should We Improve the Thresholds?

Simple Summary

The ideal treatment for hepatocellular carcinoma (HCC) is liver transplantation (LT), which both eliminates the HCC and cures the diseased liver. Once considered an experimental treatment with dismal survival rates, LT for HCC entered a new era with the establishment of the Milan criteria over 20 years ago. However, over the last two decades, the Milan criteria, which are based on tumor morphology, have come under intense scrutiny and are now largely regarded as too restrictive, and limit the access of transplantation for many patients who would otherwise achieve good clinical outcomes. The liver transplant community has been making every effort to reach a goal of establishing more reliable selection criteria. This article addresses how the criteria have been extended, as well as the concept of pre-transplant down-staging to maximize the eligibility.

Abstract

Hepatocellular carcinoma (HCC) is the third highest cause of cancer-related mortality, and liver transplantation is the ideal treatment for this disease. The Milan criteria provided the opportunity for HCC patients to undergo LT with favorable outcomes and have been the international gold standard and benchmark. With the accumulation of data, however, the Milan criteria are not regarded as too restrictive. After the implementation of the Milan criteria, many extended criteria have been proposed, which increases the limitations regarding the morphological tumor burden, and incorporates the tumor’s biological behavior using surrogate markers. The paradigm for the patient selection for LT appears to be shifting from morphologic criteria to a combination of biologic, histologic, and morphologic criteria, and to the establishment of a model for predicting post-transplant recurrence and outcomes. This review article aims to characterize the various patient selection criteria for LT, with reference to several surrogate markers for the biological behavior of HCC (e.g., AFP, PIVKA-II, NLR, 18F-FDG PET/CT, liquid biopsy), and the response to locoregional therapy. Furthermore, the allocation rules in each country and the present evidence on the role of down-staging large tumors are addressed.

Predictors of Macrovascular Invasion and Extrahepatic Metastasis in Treatment Naive Hepatocellular Carcinoma: When Is [18F] FDG PET/CT Relevant?

Purpose

Hypermetabolic macrovascular invasion (MVI) and extrahepatic metastasis (EHM) occur in aggressive hepatocellular carcinoma (HCC) and carry unfavorable prognosis. [¹⁸F] FDG PET/CT, despite having low sensitivity in primary HCC, is valuable in patients with aggressive HCC for detection of hypermetabolic MVI and EHM. The study aimed at identifying the parameters that could predict hypermetabolic MVI and/or EHM in treatment naive HCC patients for tailored approach to utilize [¹⁸F] FDG PET/CT.

Methods

Data of 131 treatment naive HCC patients (median age, 60 years; range, 21-80 years; 90.8% males) who underwent [¹⁸F] FDG PET/CT were retrospectively analyzed to determine the proportion of patients with hypermetabolic MVI and/or EHM. Logistic regression analysis was performed to define independent predictors of hypermetabolic MVI and/or EHM.

Results

78/131 (59.5%) patients had hypermetabolic MVI and/or EHM. 52/131 (39.7%) patients had EHM. 56/131 (42.7%) patients had hypermetabolic MVI of which, 30 had concomitant EHM with majority (90%; 27/30) having distant metastasis. 26/131 (19.8%) patients had hypermetabolic MVI without EHM while 22/131 (16.8%) patients had EHM without hypermetabolic MVI of which, majority (95.5%; 21/22) had distant metastasis. Hypermetabolic MVI was associated with EHM (χ² = 7.868; p value = 0.007). AFP > 93.7 ng/ml, SUVmax > 3.5, and maximum tumor size > 5.0 cm were the independent predictors of hypermetabolic MVI and/or EHM.

Conclusion

In treatment naive HCC patients with AFP > 93.7 ng/ml or maximum tumor size > 5.0 cm, [¹⁸F] FDG PET/CT can be valuable.

Liver Transplantation in Patients with Hepatocellular Carcinoma beyond the Milan Criteria: A Comprehensive Review

The Milan criteria (MC) were developed more than 20 years ago and are still considered the benchmark for liver transplantation (LT) in patients with hepatocellular carcinoma (HCC). However, the strict application of MC might exclude some patients who may receive a clinical benefit of LT. Several expanded criteria have been proposed. Some of these consider pretransplant morphological and biological variables of the tumor, others consider post-LT variables such as the histology of the tumor, and others combine pre- and post-LT variables. More recently, the HCC response to locoregional treatments before transplantation emerged as a surrogate marker of the biological aggressiveness of the tumor to be used as a better selection criterion for LT in patients beyond the MC at presentation. This essential review aims to present the current data on the pretransplant selection criteria for LT in patients with HCC exceeding the MC at presentation based on morphological and histological characteristics of the tumor and to critically discuss those that have been validated in clinical practice. Moreover, the role of HCC biological markers and the tumor response to downstaging procedures as new tools for selecting patients with a tumor burden outside of the MC for LT is evaluated.

18F-FDG-PET/CT Imaging for Gastrointestinal Malignancies

Gastrointestinal malignancies encompass a variety of primary tumor sites, each with different staging criteria and treatment approaches. In this review we discuss technical aspects of 18F-FDG-PET/CT scanning to optimize information from both the PET and computed tomography components. Specific applications for 18F-FDG-PET/CT are summarized for initial staging and follow-up of the major disease sites, including esophagus, stomach, hepatobiliary system, pancreas, colon, rectum, and anus.

Diagnostic test accuracies of F-18 FDG PET/CT for prediction of microvascular invasion of hepatocellular carcinoma: A meta-analysis

PURPOSE

The aim of the current meta-analysis was to evaluate diagnostic accuracies of preoperative F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) for prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) patients.

METHODS

The scientific database such as PubMed, Cochrane, and Embase database were searched for studies evaluating diagnostic accuracies of preoperative F-18 FDG PET or PET/CT for prediction of MVI in HCC patients up to November 30, 2020.

RESULTS

Fourteen eligible studies (1276 patients) were enrolled. The pooled sensitivity for F-18 FDG PET or PET/CT was 0.67 (95% CI; 0.57-0.76) with heterogeneity and a pooled specificity of 0.80 (95% CI; 0.74-0.85) with heterogeneity. Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 3.3 (95% CI; 2.5-4.5) and negative likelihood ratio (LR-) of 0.41 (95% CI; 0.31-0.55). The pooled diagnostic odds ratio (DOR) was 8 (95% CI; 5-14). Summary receiver operating characteristic (ROC) curve indicates that the area under the curve was 0.81 (95% CI; 0.78-0.84).

CONCLUSION

The current meta-analysis showed a low sensitivity and moderate specificity of F-18 FDG PET or PET/CT for the prediction of MVI in HCC patients. F-18 FDG PET or PET/CT might not be useful for the preoperative prediction of MVI in HCC patients and should not be used to exclude MVI. Therefore, cautious application and interpretation should be paid to the F-18 FDG PET or PET/CT for the prediction of MVI in HCC patients preoperatively.

Investigating the value of pre-treatment 18F-FDG PET/CT in predicting the pathological characteristic of hepatocellular carcinoma and recurrence after liver transplantation

PURPOSE

The aim of this study is to investigate the value of pre-treatment ¹⁸F-FDG PET/CT in predicting the pathological characteristic of HCC and recurrence after liver transplantation (LT).

METHODS

A total of 34 patients who underwent ¹⁸F-FDG PET/CT before LT for HCC and did not receive any other treatment were retrospectively enrolled in the study. The maximal standard uptake value of the tumor (T-SUVmax), normal liver tissues (L-SUVmax), and mediastinal blood pool (B-SUVmax) were derived, followed by the calculations of the T-SUVmax/L-SUVmax (T/L) and the T-SUVmax/B-SUVmax (T/B) ratios. Combined with the post-transplantation pathological results and ROC curve, the performance in predicting the pathological characteristic and the recurrence after LT were evaluated.

RESULTS

The AUCs for T-SUVmax, T/L, and T/B in predicting the pathological grade of tumors were 0.820, 0.784, and 0.806, respectively. Alternatively, the AUCs for T-SUVmax, T/L, and T/B in predicting the recurrence after LT were 0.865, 0.899, and 0.931, respectively. The individual cutoff values were 5.0, 1.7, and 2.2, corresponding to a predication accuracy of 88.2%, 85.3%, and 88.2%, respectively. In addition, the AUCs for T/B in predicting microvascular invasion (mVI) and liver capsular invasion (LCI) were 0.825 and 0.788, respectively.

CONCLUSION

The pre-treatment ¹⁸F-FDG PET/CT is effective for predicting recurrence of HCC after LT. In addition, it demonstrates values for predicting the pathological characteristic of HCC such as pathological grade, mVI, and LCI.

Clinical impact of anatomical resection on long-term outcomes after hepatectomy for primary solitary hepatocellular carcinoma with or without preoperative positron emission tomography positivity

Background

There is little evidence indicating that anatomical resection (AR) is associated with improved survival in patients with solitary hepatocellular carcinoma (HCC) who were preoperatively evaluated by positron emission tomography (PET). The aim of our study was to compare the oncologic outcomes of AR in PET-positive versus PET-negative patients with HCC.

Methods

From January 2007 to September 2015, 259 patients with preoperative PET underwent hepatectomy as the primary treatment for solitary HCC. Patients were divided into four groups according to PET uptake and hepatectomy type [AR or non-anatomical resection (NAR)]: Group 1 (PET-negative and AR, n=62); Group 2 (PET-negative and NAR, n= 46); Group 3 (PET-positive and AR, n=100); Group 4 (PET-positive and NAR, n=51).

Results

PET positivity was associated with higher protein induced by vitamin K antagonist-II (P=0.025), lager tumor size (P=0.05), microvascular invasion (MVI) (P=0.012), and portal vein invasion (P=0.031). In Kaplan-Meier analysis for RFS, Group 1 showed remarkable difference from Group 3 and Group 4 (P=0.045, P=0.023, respectively). In the PET-positive subgroup with HCC under 3 cm, AR was associated with better RFS than NAR (P=0.016).

Conclusions

A combination of AR and PET negativity showed good prognosis in long-term outcomes. Finally, AR can decrease the risk of tumor recurrence in patients with a solitary PET-positive HCC less than 3 cm.

Prognostic value of 18F-fluorodeoxyglucose positron emission tomography in patients with small hepatocellular carcinoma treated by radiofrequency ablation

BACKGROUND

¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake in hepatocellular carcinoma (HCC) is significantly associated with early recurrence and survival after curative surgical resection. However, there are no reports regarding the relationship between ¹⁸F-FDG uptake and outcomes after radiofrequency ablation (RFA). A prospective cohort study was conducted to evaluate the prognostic value of ¹⁸F-FDG positron emission tomography (PET) in HCC patients after RFA.

METHODS

A total of 121 consecutive patients with primary HCC (≤3 tumors, of diameter ≤ 3 cm) without vascular invasion on imaging were examined by ¹⁸F-FDG-PET computed tomography prior to RFA. An HCC with a component of ¹⁸F-FDG uptake visibly stronger than that of surrounding liver was defined as ¹⁸F-FDG-PET positive.

RESULTS

The median follow-up period was 1267 days. There were 110 ¹⁸F-FDG-PET negative and 11 positive tumors. The cumulative 1-year recurrence rates in the ¹⁸F-FDG negative and positive groups were 30 and 64% (P = 0.017), respectively, and cumulative 1-year metastatic recurrence rates were 6 and 36% (P < 0.001), respectively. The cumulative 5-year survival rates were 88 and 22% (P < 0.001), respectively. Multivariate analysis revealed ¹⁸F-FDG-PET positivity and tumor size as independent factors related to metastatic recurrence and survival after RFA.

CONCLUSIONS

¹⁸F-FDG-PET positivity was significantly associated with outcomes after RFA. RFA should not be readily selected as the first-line treatment for small HCC that includes a component of visually strong ¹⁸F-FDG uptake.

Predicting tumor recurrence using metabolic indices of 18F-FDG PET/CT prior to orthotopic liver transplantationfor hepatocellular carcinoma

The present study analyzed the ability of metabolic burden indices from ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to predict tumor recurrence following orthotopic liver transplantation (OLT) in patients with hepatocellular carcinoma (HCC). Seven major metabolic indices were measured by ¹⁸F-FDG PET/CT in 93 patients with HCC, prior to OLT. The Mann-Whitney U test was then used to predict the association of metabolic indices, including the maximum standardized uptake value (SUVmax), tumor-to-mediastinum SUV ratio, tumor-to-normal-liver SUV ratio, SUV normalized to lean body mass metabolic tumor volume (MTV), total lesion glycolysis (TLG) and uptake-volume product (UVP), with the recurrence risk. The Deauville-like scoring system was used to quantify the recurrence risk. Univariate and multivariable Cox regression models were performed to determine survival rate. The results showed that Deauville-like score (PET-negative vs. -positive), MTV (cutoff value, 13.36), TLG (cutoff value, 62.21) and UVP (cutoff value, 66.60) had high prediction performance for tumor recurrence (P<0.05). TLG had the highest receiver operating characteristics area under the curve of 0.725. Among the clinical factors, high level of α-fetoprotein (AFP, ≥144 ng/ml), Milan criteria, tumor number (>3), involvement of both right and left lobes, and tumor size (>5 cm) were found to be significant predictors of tumor recurrence. Patients in the low metabolic group had longer recurrence-free survival (RFS) times compared with those in the high metabolic group, regardless of whether they met the Milan criteria or not. AFP, uptake-volume product according the SUV mean of mediastinum (UVP-M), Milan criteria, lymph node metastasis, and the number of tumors were significant prognostic factors for RFS (P<0.05) in both univariate and multivariate survival analyses. Additionally, the MVI was a significant prognostic factor based on univariate survival analyses. Overall, the present study demonstrated the metabolic burden indices measured by PET/CT, Deauville-like score, MTV, TLG and UVP as significant prognostic factors in patients with HCC following OLT. The combination of metabolic indices measured by PET/CT and the existing criteria, such as the Milan criteria, may play an important role in evaluating the suitability of OLT in specific patients.

Addition of [18 F]Fluorodeoxyglucose Positron Emission Tomography With Computed Tomography to Cross-Sectional Imaging Improves Staging and Alters Management in Hepatocellular Carcinoma

In this work, we characterize the value of positron emission tomography (PET) with computed tomography (CT) in combination with cross-sectional imaging for staging and prognostication of hepatocellular carcinoma (HCC) patients. In this retrospective cohort study, HCC patients underwent PET-CT after initial staging with contrast-enhanced CT or magnetic resonance imaging (MRI). The benefit of PET-CT was measured by the identification of new HCC lesions, and potential harm was quantified by the number of false positives and subsequent diagnostic evaluation. We used multivariate Cox regression analysis to evaluate the association between the highest grade on PET-CT with the risk of extrahepatic metastasis, progression-free, and overall survival. Among 148 patients, PET-CT detected additional extrahepatic metastasis in 11.9% of treatment-naïve and 13.8% of treatment-experienced patients. PET-CT changed the Barcelona Clinic Liver Cancer (BCLC) staging in 5.9% of treatment-naïve and 18.8% of treatment-experienced patients compared with CT/MRI alone, changing HCC management in 9.9% and 21.3% of patients, respectively. Of the patients, 5% (n = 8) experienced severe physical harm requiring additional procedures to evaluate extrahepatic findings. High tumor grade on PET-CT was independently associated with a higher likelihood of extrahepatic metastasis (hazard ratio [HR], 17.1; 95% confidence interval [CI], 3.6-81.5) and worse overall survival (HR, 2.4; 95% CI, 1.4-4.3). Treatment-experienced patients (versus treatment-naïve patients; HR, 9.7; 95% CI, 1.9-49.4) and BCLC stage A (HR, 8.2; 95% CI, 1.5-45.9; P < 0.01) and BCLC stage B (HR, 20.6; 95% CI, 1.5-282.2; P < 0.05) were more likely to have an upstaging with PET-CT compared with BCLC stage C (reference). PET-CT provides prognostic information and improves tumor staging beyond CT/MRI alone, with subsequent changes in management for patients with HCC.

Hypoxia-induced modulation of glucose transporter expression impacts 18F-fluorodeoxyglucose PET-CT imaging in hepatocellular carcinoma

PURPOSE

To investigate the molecular mechanisms underlying the variable standard uptake value (SUV) of ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET-CT) imaging in hepatocellular carcinoma (HCC) and whether hypoxia-induced glucose transporter expression contributes to the progression of HCC and the rate of glycolysis in HCC cells.

MATERIALS AND METHODS

Sixteen HCC specimens obtained from patients who underwent pre-treatment staging with ¹⁸F-FDG PET-CT imaging were divided into high maximum SUV (SUV_max > 8) and low SUV_max (SUV_max < 5) groups and employed for whole-genome gene expression profiling using GeneChip Human Genome U133 Plus 2.0 Arrays. The relationship between SUV_max and the expression of glucose transporters 1 and 3 (GLUT1 and GLUT3) was further validated using immunohistochemical analysis. The expression of GLUT1 and GLUT3 in different HCC cells under hypoxia and normoxia conditions were monitored by quantitative reverse transcription PCR (RT-qPCR). Glycolysis and FDG uptake by HCC cells were measured using the Seahorse XF glycolysis stress test and ¹⁸F-FDG PET-CT imaging. The effect of GLUT1 and GLUT3 on glucose uptake in HCC cells was examined using the fluorescent D-glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (2-NBDG) followed by detection of fluorescence produced by the cells using flow cytometry.

RESULTS

Glucose transporters are differentially expressed between samples from HCC patients with high and low SUV_max. In particular, over-expression of GLUT1 and GLUT3 in high SUV_max patients was correlated with high glucose uptake and overall survival. The expression of GLUT1 and GLUT3 was significantly induced by hypoxia in different HCC cells. High expression of GLUT1 and GLUT3 in HCC cells were correlated with high rates of glycolysis and 18F-FDG uptake. Therefore, our data suggested that hypoxia-induced glucose transporters expression could result in the variations of ¹⁸F-FDG PET-CT imaging and progression of HCC, contributing to more aggressive disease phenotypes like large tumor size, recurrence, and poor survival.

CONCLUSION

Over-expression of GLUT1 and GLUT3 significantly increase glucose uptake in HCC cells. Hypoxia-induced glucose transporters expression may therefore be a contributing variable in ¹⁸F-FDG PET-CT imaging and progression in HCC.

18F-FDG PET/CT predicts microvascular invasion and early recurrence after liver resection for hepatocellular carcinoma: A prospective observational study

BACKGROUND

This study assessed the prognostic value of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) in the prediction of MVI and early recurrence following resection.

METHOD

This prospective study (ClinicalTrials.gov ID: NCT02145013) included 78 consecutive HCC patients who underwent 18F-FDG PET/CT before curative-intent resection from 2014 to 2017. Prognostic factors available before surgery for predicting MVI and early recurrence (≤2 years) were identified by univariate and multivariate analyses.

RESULTS

The 18F-FDG PET/CT result was positive in 30 (38%) patients. MVI was present in 33% (26/78) of specimens. Early recurrence occurred in 19% (14/74) of surviving patients. PET/CT positivity was the sole independent predictor of MVI (odds ratio [OR] = 3.6, 95% confidence interval [CI] = 1.1-11.2; p = 0.03), with a specificity and sensitivity for predicting MVI of 73% and 62%, respectively. Analysis of variables available before surgery showed that PET/CT positivity (hazard ratio [HR] = 5.8, 95% CI = 1.6-20.4; p = 0.006) and the male sex (HR = 6.6; 95% CI = 1.8-24.2; p = 0.005) were independent predictors of early recurrence.

CONCLUSION

18F-FDG PET/CT predicts MVI and early recurrence after surgery for HCC and could be used to select patients for neoadjuvant treatment.

18F-fludeoxyglucose positron emission tomography for diagnosis of HCC: implications for therapeutic strategy in curative and non-curative approaches

Hepatocellular carcinoma (HCC) is a global health issue with increasing incidence and high mortality rate. Depending on the tumor load and extent of underlying liver cirrhosis, aggressive surgical treatment by hepatectomy or liver transplantation (LT) may lead to cure, whereas different modalities of liver-directed locoregional or systemic tumor treatments are currently available for a noncurative approach. Apart from tumor burden and grade of liver dysfunction, assessment of prognostic relevant biological tumor aggressiveness is vitally important for establishing a promising multimodal therapeutic strategy and improving the individual treatment-related risk/benefit ratio. In recent years, an increasing body of clinical evidence has been presented that ¹⁸F-fludeoxyglucose (¹⁸F-FDG) positron emission tomography (PET), which is a standard nuclear imaging device in oncology, may serve as a powerful surrogate for tumor invasiveness and prognosis in HCC patients and, thereby, impact individual decision making on most appropriate therapy concept. This review describes the currently available data on the prognostic value of ¹⁸F-FDG PET in patients with early and advanced HCC stages and the resulting implications for treatment strategy.

The power of tumor sizes in predicting the survival of solitary hepatocellular carcinoma patients

Background

Vascular invasion, rather than tumor size, was applied into the 7th edition of the AJCC TNM staging system to predict survival of solitary hepatocellular carcinoma (HCC) patients. However, does this mean tumor size is of little value in prognostic prediction? The current study was designed to explore the prognostic ability of tumor sizes in solitary HCC.

Methods

A total of 18 591 patients with solitary HCC categorized as T1 and T2 were retrieved from the Surveillance Epidemiology and End Results (SEER) database. The Cox proportional hazards regression model was adopted to evaluate the impact of tumor sizes on overall survival (OS) and disease‐specific survival (DSS) in general and in subgroups stratified by vascular invasion and surgery type.

Results

Large tumor sizes (>39 mm) were associated with unfavorable clinicopathologic characteristics. Compared with tumors ≤30 mm, tumors between 31‐50 mm and tumors >50 mm showed significantly worse OS and DSS in general using multivariate analysis (all P < 0.001). In subgroup analyses, for patients without vascular invasion, tumor size was a notable prognostic indicator for OS in the radiofrequency ablation group (P < 0.001), rather than in the liver resection or transplantation group. Nevertheless, for patients with vascular invasion, tumor sizes exhibited a notable impact on OS in the liver resection and transplantation group.

Conclusions

The AJCC TNM staging system for solitary HCC would be more comprehensive if tumor sizes were integrated into the T2 classification. Additionally, for T1 patients, tumor sizes play no role in the choice between resection and transplantation.

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.

Clinical usefulness of FDG-PET in patients with hepatocellular carcinoma undergoing surgical resection

Backgrounds/Aims

Diagnosis and staging of hepatocellular carcinoma (HCC) is critical because of the variety of treatment methods and prognosis. [¹⁸F]fludeoxyglucose-positron emission tomography/computed tomography ([¹⁸F]FDG-PET/CT) has been suggested as a diagnostic modality in HCC. The purpose of this study is to evaluate the accuracy of FDG-PET for staging of HCC after surgical resection and histological confirmation.

Methods

We retrospectively collected data of 56 patients that underwent FDG-PET before surgical resection for HCC March 2011–May 2017, all of whom were suitable for resection by conventional HCC staging. Results of the maximal standardized uptake value (SUVmax) were compared with histological confirmation.

Results

A larger tumor size was related with higher SUVmax (≥4.9). The serum alpha-feto protein was associated with SUVmax. Recurrence rate was higher in patients with higher SUVmax and patients with lower SUVmax had a better survival rate.

Conclusions

The SUVmax correlates well with tumor size and factors associated with biological behavior of HCC such as alpha-feto protein, and it could be a beneficial modality in providing prognostic information for HCC.

Combining 18F-FDG positron emission tomography with Up-to-seven criteria for selecting suitable liver transplant patients with advanced hepatocellular carcinoma

The Up-to-seven (UTS) criteria (sum of tumor size and number not exceeding 7) for indicating liver transplantation (LT) in hepatocellular carcinoma (HCC) were originally based on explant pathology features and absence of microvascular invasion (MVI). ¹⁸F-fludeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) was shown to indicate the risk of MVI and tumor recurrence. The aim of this study was to analyze the prognostic significance of the clinical UTS criteria when being combined with PET-status of the tumor. Data of 116 liver transplant patients were subject to retrospective analysis. Five-year recurrence-free survival (RFS) rates in patients meeting (n = 85) and exceeding (n = 21) the radiographic UTS criteria were 81% and 55.1%, respectively (p = 0.014). In the UTS In subset, RFS was significantly better in PET-negative (94.9%) than in PET-positive patients (48.3%; p < 0.001). In the UTS Out subset, 5-year RFS rates were 87.1% and 19% in patients with non- ¹⁸F-FDG-avid and ¹⁸F-FDG-avid tumors (p < 0.001), respectively. Positive PET-status was identified as the only independent clinical predictor of tumor recurrence in beyond UTS patients (Hazard ratio [HR] 19.25; p < 0.001). Combining radiographic UTS criteria with FDG-PET may safely expand the HCC selection criteria for LT.

Hepatocellular carcinoma: when is liver transplantation oncologically futile?

Selection criteria of patients with hepatocellular carcinoma (HCC) for liver transplantation (LT) have been progressively expanded since the introduction of the Milan criteria. Transplanting patients with unfavourable tumor characteristics increases the risk of tumor recurrence and impacts post-transplant survival. Although tumor number and size are the basis of widely accepted selection criteria and correlate with tumor grading and microvascular invasion, stronger predictors of tumor recurrence have been recently identified. These surrogates of aggressive tumor biology include non-response to pre-transplant treatment, rapid recurrence within the first months after treatment, increased alpha-fetoprotein (AFP) concentrations, ¹⁸F-FDG positron emission tomography (PET) positive HCCs and poor differentiation and microvascular invasion in histology. The presence of any of these risk factors significantly increases the risk of tumor recurrence in patients within and beyond the Milan criteria. Especially the combination of two or more of these factors is associated with an inacceptably high recurrence risk and can render LT oncologically futile even in patients not exceeding the Milan criteria. In contrast, in absence of these risk factors also patients exceeding expanded selection criteria may undergo LT with low recurrence risk and favourable post-transplant outcome. In selected cases this may even be applicable to patients with macrovascular invasion, who are conventionally excluded from LT. The main focus of this article is to review LT for HCC in the light of recurrence rates and to explore at what tumor stage transplantation becomes futile.