Increased 18F-FDG uptake of hepatocellular carcinoma on positron emission tomography independently predicts tumor recurrence in liver transplant patients

Quarter-Century PET/Computed Tomography Transformation of Oncology: Hepatobiliary and Pancreatic Cancer

[18F] Fluorodeoxyglucose (18F-FDG) PET/CT can improve the staging accuracy and clinical management of patients with hepatobiliary and pancreatic cancers, by detection of unsuspected metastases. 18F-FDG PET/CT metabolic parameters are valuable in predicting treatment response and survival. Metabolic response on 18F-FDG PET/CT can predict preoperative pathologic response to neoadjuvant therapy in patients with pancreatic cancer and determine prognosis. Several novel non-FDG tracers, such as 68Ga prostate-specific membrane antigen (PSMA) and 68Ga-fibroblast activation protein inhibitor (FAPI) PET/CT, show promise for imaging hepatobiliary and pancreatic cancers with potential for radioligand therapy.

Predicting Overall Survival with Deep Learning from 18F-FDG PET-CT Images in Patients with Hepatocellular Carcinoma before Liver Transplantation

Positron emission tomography and computed tomography with 18F-fluorodeoxyglucose (18F-FDG PET-CT) were used to predict outcomes after liver transplantation in patients with hepatocellular carcinoma (HCC). However, few approaches for prediction based on 18F-FDG PET-CT images that leverage automatic liver segmentation and deep learning were proposed. This study evaluated the performance of deep learning from 18F-FDG PET-CT images to predict overall survival in HCC patients before liver transplantation (LT). We retrospectively included 304 patients with HCC who underwent 18F-FDG PET/CT before LT between January 2010 and December 2016. The hepatic areas of 273 of the patients were segmented by software, while the other 31 were delineated manually. We analyzed the predictive value of the deep learning model from both FDG PET/CT images and CT images alone. The results of the developed prognostic model were obtained by combining FDG PET-CT images and combining FDG CT images (0.807 AUC vs. 0.743 AUC). The model based on FDG PET-CT images achieved somewhat better sensitivity than the model based on CT images alone (0.571 SEN vs. 0.432 SEN). Automatic liver segmentation from 18F-FDG PET-CT images is feasible and can be utilized to train deep-learning models. The proposed predictive tool can effectively determine prognosis (i.e., overall survival) and, thereby, select an optimal candidate of LT for patients with HCC.

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.

Changes in hepatocellular carcinoma aggressiveness characteristics with an increase in tumor diameter

BACKGROUND

Hepatocellular carcinoma prognosis depends on both liver and tumor determinants, especially on maximum tumor diameter, multifocality, and presence of portal vein thrombosis, despite apparently complete tumor removal by resection or liver transplantation.

AIMS

To examine parameters of hepatocellular carcinoma aggressiveness as tumor size increases.

METHODS

A large hepatocellular carcinoma database was examined for trends in serum alpha-fetoprotein and the percentage of patients with macroscopic portal vein thrombosis or tumor multifocality.

RESULTS

A total of 13,016 hepatocellular carcinoma patients were identified having full tumor and survival data. Of these, 76.56% were male and 23.44% were female, with a median age of 64.4 years. We found that as the maximum tumor diameter increased, there was a significant trend for increased alpha-fetoprotein levels (P<0.001) and an increased percentage of patients with either portal vein thrombosis or tumor multifocality, each P<0.0001. Furthermore, the increases of both alpha-fetoprotein and portal vein thrombosis were proportionately greater than the related maximum tumor diameter increases. These trends of increased alpha-fetoprotein, portal vein thrombosis, and multifocality with increasing maximum tumor diameter had non-linear patterns. Within alpha-fetoprotein and multifocality trends, there were identifiable sub-trends associated with specific maximum tumor diameter ranges.

CONCLUSIONS

The greater fold-increases in alpha-fetoprotein and portal vein thrombosis compared with increases in maximum tumor diameter imply that hepatocellular carcinoma characteristics may change with increasing size to a more aggressive phenotype, suggesting that follow-up tumor sampling might be useful, in addition to baseline tumor sampling, for optimal therapeutic choices to be made.

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.

Selecting patients with hepatocellular carcinoma for liver transplantation: incorporating tumor biology criteria

Liver transplantation (LT) is the optimal therapeutic option for patients with liver cirrhosis and hepatocellular carcinoma (HCC). Due to universal donor shortage, only the patients with limited tumor burden (under the so-called Milan criteria) are considered as potential candidates for LT in most institutions. It is expected that in the near future, more liver grafts will be available for patients with HCC due to the implementation of new direct antivirals against hepatitis C, leaving a prone scenario to consider expanding Milan criteria. A moderate expansion of Milan criteria could be implemented without increasing the risk of tumor recurrence if patients with favorable biological behavior are carefully selected. Incorporating information regarding tumor biology in the decision-making algorithm would result in a more rational use of LT in patients with HCC. In the present review, surrogate markers of tumor biology are critically evaluated as potential tools to be combined with existing radiological criteria. In addition, the current state of liquid biopsy is discussed, as this cutting-edge technology may reshape the management of HCC in the upcoming years.

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.

Preoperative prediction of microvascular invasion of hepatocellular carcinoma using 18F-FDG PET/CT: a multicenter retrospective cohort study

PURPOSE

The aim of this study was to assess the potential of tumor ¹⁸F-fluorodeoxyglucose (FDG) avidity as a preoperative imaging biomarker for the prediction of microvascular invasion (MVI) of hepatocellular carcinoma (HCC).

METHODS

One hundred and fifty-eight patients diagnosed with Barcelona Clinic Liver Cancer stages 0 or A HCC (median age, 57 years; interquartile range, 50-64 years) who underwent ¹⁸F-FDG positron emission tomography with computed tomography (PET/CT) before curative surgery at seven university hospitals were included. Tumor FDG avidity was measured by tumor-to-normal liver standardized uptake value ratio (TLR) of the primary tumor on FDG PET/CT imaging. Logistic regression analysis was performed to identify significant parameters associated with MVI. The predictive performance of TLR and other clinical variables was assessed using receiver operating characteristic (ROC) curve analysis.

RESULTS

MVI was present in 76 of 158 patients with HCCs (48.1%). Multivariable logistic regression analysis revealed that TLR, serum alpha-fetoprotein (AFP) level, and tumor size were significantly associated with the presence of MVI (P < 0.001). Multinodularity was not significantly associated with MVI (P = 0.563). The area under the ROC curve (AUC) for predicting the presence of MVI was best with TLR (AUC = 0.704), followed by tumor size (AUC = 0.685) and AFP (AUC = 0.670). We were able to build an improved prediction model combining TLR, tumor size, and AFP by using multivariable logistic regression modeling (AUC = 0.756).

CONCLUSIONS

Tumor FDG avidity measured by TLR on FDG PET/CT is a preoperative imaging biomarker for the prediction of MVI in patients with HCC.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

Predictive Value of 18F-FDG PET/CT for Vascular Invasion in Patients With Hepatocellular Carcinoma Before Liver Transplantation

BACKGROUND

Positron emission tomography-computed tomography using F-fluorodeoxyglucose (F-FDG PET/CT) has been widely used in oncology. Vascular invasion of hepatocellular carcinoma (HCC) is associated with a high risk of tumor recurrence and low survival rates after liver transplantation (LT). This retrospective study determined the predictive value of F-FDG PET/CT for vascular invasion in patients with HCC before LT.

METHODS

Sixty-five patients with HCC who underwent F-FDG PET/CT before LT were retrospectively included between January 2010 and July 2012. Volumes of interest (VOIs) were drawn for the tumors and normal liver tissues, and the standardized uptake value (SUV) in each VOI was measured. The maximal SUV (SUVmax) of the tumor, the ratio of tumor SUVmax to normal liver SUVmax (TSUVmax/LSUVmax), and the ratio of tumor SUVmax to normal liver SUVmean (TSUVmax/LSUVmean) were measured. The predictive value of metabolic parameters and conventional prognostic factors were analyzed.

RESULTS

Vascular invasion was pathologically confirmed in 15 (23.08%) of 65 patients. Compared with patients without vascular invasion, patients with vascular invasion exhibited significantly higher serum alpha-fetoprotein (AFP) (P < 0.001), larger tumor size (P = 0.001), higher tumor number (P = 0.017), and higher SUVmax, TSUVmax/LSUVmax ratio, and higher TSUVmax/LSUVmean ratio (P = 0.008, P = 0.002, and P = 0.006, respectively). Univariate analysis revealed that SUVmax, TSUVmax/LSUVmax ratio, and TSUVmax/LSUVmean ratio of FDG PET/CT were significantly associated with vascular invasion in patients with HCC before LT (P = 0.019, P = 0.018, and P = 0.015, respectively). Multivariate analysis revealed that the TSUVmax/LSUVmean ratio of F-FDG PET/CT was a significant predictor of vascular invasion (P = 0.04) and that the TSUVmax/LSUVmax ratio of F-FDG PET/CT was an independent predictor of vascular invasion, although this finding demonstrated borderline statistical significance (P = 0.06) in patients with HCC before LT.

CONCLUSIONS

According to the study results, the TSUVmax/LSUVmean ratio is an independent and significant predictor of vascular invasion, and the TSUVmax/LSUVmax ratio of F-FDG PET/CT is an independent predictor of vascular invasion, which is the main negative outcome after LT. Therefore, FDG PET/CT can provide vital information for determining prognosis and selecting an optimal candidate of LT for HCC.

Metabolic Activity by 18F-FDG-PET/CT Is Prognostic for Stage I and II Pancreatic Cancer

PURPOSE

Metabolic activity, as defined by F-FDG uptake on PET, is a prognostic marker for multiple malignancies; however, no study has examined the prognostic value of imaging with FDG PET in stage I and II pancreatic cancer. We examined the value of PET FDG uptake in early-stage pancreatic cancer patients.

METHODS

We identified patients with early-stage pancreatic cancer (I-II) who had FDG PET scan performed as part of their preoperative evaluation. The patients were divided into either high or low FDG uptake according to the median primary tumor standard uptake value (SUVmax). Our primary end points were overall survival (OS) and recurrence-free survival (RFS). Kaplan-Meier estimate was used for survival analysis. Pathologic data were compared using the Fisher exact and χ tests.

RESULTS

One hundred five patients were identified: 51 patients with low FDG uptake and 54 patients with high FDG uptake. Eighty-five patients (81%) had PET avid tumors, whereas 20 (19%) patients did not. High FDG uptake correlated with pathologic stage (P = 0.012). Patients with low FDG uptake had significantly better median OS than patients with high FDG uptake (28 vs. 16 months; P = 0.036). Patients with low-FDG uptake had significantly longer median RFS than patients with high FDG uptake (14 vs. 12 months; P = 0.049).

CONCLUSIONS

Low FDG uptake in PET scans in patients with stage I and II pancreatic cancer correlates with improved OS and RFS. This supports the concept that glucose metabolic pathways are important in pancreatic cancer biology and that PET scan activity can be used as a prognostic biomarker after pancreatectomy.

18F-FDG PET in Liver Transplantation Setting of Hepatocellular Carcinoma: Predicting Histology?

PURPOSE

The aim of this study was to evaluate the prognostic value of F-FDG PET/CT by predicting histopathological findings in the pretransplant evaluation of patients with hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

F-FDG PET/CT findings of 34 patients with HCC who underwent liver transplantation were reviewed retrospectively. Visual and quantitative analysis (tumor standardized uptake values normalized to the background activity of the liver: SUVmax T/L) was done. PET tumor characteristics were compared with the histological analysis (differentiation and microvascular invasion). All patients were followed up (mean, 12 months).

RESULTS

Ten patients showed tumoral uptake greater than background activity (PET+). Higher-grade tumor was more common in the F-FDG-avid tumor group (P < 0.05). PET+ also showed more microvascular invasion at explant pathology (P < 0.05). Only 1 patient PET+ developed HCC early recurrence (4 months) with an SUVmax T/L of 1.64.

CONCLUSIONS

F-FDG uptake is predictive for microvascular invasion and tumor differentiation. This examination has a prognostic value regarding tumor recurrence after liver transplantation for HCC.

Liver transplantation for hepatocellular carcinoma beyond the Milan criteria: A review

Liver transplantation (LT) has been accepted as an effective therapy for hepatocellular carcinoma (HCC). The Milan criteria (MC) are widely used across the world to select LT candidates in HCC patients. However, the MC may be too strict because a substantial subset of patients who have HCC exceed the MC and who would benefit from LT may be unnecessarily excluded from the waiting list. In recent years, many extended criteria beyond the MC were raised, which were proved to be able to yield similar outcomes compared with those patients meeting the MC. Because the simple use of tumor size and number was insufficient to indicate HCC biological features and to predict the risk of tumor recurrence, some biological markers such as Alpha-fetoprotein, Des-Gamma-carboxy prothrombin and the neutrophil-to-lymphocyte ratio were useful in selecting LT candidates in HCC patients beyond the MC. For patients with advanced HCC, downstaging therapy is an effective way to reduce the tumor stage to fulfill the MC by using liver-directed therapy such as transarterial chemoembolization, radiofrequency ablation and percutaneous ethanol injection. This article reviews the recent advances in LT for HCC beyond the MC.

Prediction of Posttransplantation Recurrence of Hepatocellular Carcinoma Using Metabolic and Volumetric Indices of 18F-FDG PET/CT

(18)F-FDG PET is an effective method of predicting recurrence of hepatocellular carcinoma (HCC) after liver transplantation. We compared recently introduced metabolic and volumetric (18)F-FDG PET/CT indices with the current clinicopathologic predictors for ability to predict recurrence.

METHODS

In total, 110 HCC patients who underwent (18)F-FDG PET and liver transplantation were enrolled. On PET, SUVs and tumor-to-background ratios (TBRs) were measured as metabolic activity indices. Various metabolic tumor volumes and uptake-volume products (UVP) were also measured as volumetric indices. The ability of these indices and other clinicopathologic factors to predict recurrence was compared.

RESULTS

All metabolic and volumetric indices were significant for recurrence prediction on receiver-operating-characteristic curve analyses (P < 0.001). On univariate survival analyses, all PET indices-as well as tumor size, tumor number, the Milan criteria, tumor grade, vascular invasion, and T-stage-were significant factors. However, on multivariate analyses, tumor size, tumor grade, maximum TBR, and UVP calculated by inferior vena cava activity were significant factors (P = 0.004, 0.014, 0.009, and 0.021, respectively). When the Milan criteria and PET factors were included in the multivariate analysis, the Milan criteria (P = 0.029), maximum TBR (P < 0.001), and UVP (P = 0.016) were significant.

CONCLUSION

Volumetric and metabolic activity indices of (18)F-FDG PET are effective predictors of posttransplantation HCC recurrence. In addition to clinicopathologic factors, these indices need to be considered in the selection of candidates for liver transplantation.

Application of Different Imaging Methods in the Early Diagnosis of Primary Hepatic Carcinoma

Primary hepatic carcinoma (PHC) is the one of the most common tumors and the common cause of cancer death in the world. Detecting PHC in its early stage by imaging methods may greatly increase survival rates of patients. Ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography/computed tomography are common imaging methods in the diagnosis of PHC. In this paper, the application of different imaging methods in diagnosing the primary hepatic carcinoma will be discussed.

Liver transplantation for hepatocellular carcinoma - factors influencing outcome and disease-free survival

Hepatocellular carcinoma is one of the leading causes of cancer-related death worldwide. Liver transplantation can be a curative treatment in selected patients. However, there are several factors that influence disease-free survival after transplantation. This review addresses the pre-, intra- and postoperative factors that influence the risk of tumor recurrence after liver transplantation.

Role of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography in gastrointestinal cancers

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has become a routine imaging modality for many malignancies and its use is currently increasing. In the present review article, we will summarize the evidence for FDG-PET/CT use in digestive cancers (excluding neuroendocrine tumours), and review the existing recommendations. While PET/CT is nowadays considered to be an important tool in the initial workup of oesophageal and anal cancers, new data are emerging regarding its use in assessing therapeutic efficacy, radiotherapy treatment planning, and detection of recurrence in case of isolated tumour marker elevation. Moreover, PET/CT may help decision making by detecting distant metastatic sites especially in potentially resectable metastatic colorectal cancer and, to a lesser extent, in localized gastric and pancreatic cancers. Finally, incidental focal colonic FDG uptakes require exploration by colonoscopy, as they are often associated with premalignant or malignant lesions.

[18F]fludeoxyglucose positron emission tomography and computed tomography as a prognostic tool before liver transplantation, resection, and loco-ablative therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide. Orthotopic liver transplantation (OLT) and resection are curative treatment options for well-selected patients with HCC, whereas loco-ablative therapy has been shown to prolong survival. Organ and treatment allocations for these patients are currently based on the number and size of tumors, as defined by the Milan criteria, and on functional capacity, and they are incorporated into the Barcelona Clinic Liver Cancer staging system and treatment strategy. Even though these staging criteria have markedly improved the outcomes of patients with HCC, they still lack accuracy in predicting the risk of tumor recurrence because they do not incorporate markers of tumor biology and behavior. Positron emission tomography (PET) and computed tomography (CT) with [(18) F]fludeoxyglucose ([(18) F]FDG) constitute an imaging modality for detecting tumor tissue that is metabolically active. Uptake of [(18) F]FDG is highly associated with tumor aggressiveness. In this review, we present the accumulating data on the use of [(18) F]FDG PET-CT as an in vivo biomarker and its predictive value in identifying patients at risk for HCC recurrence after liver transplantation, resection, or ablation. These data suggest that the introduction of [(18) F]FDG PET-CT into the imaging algorithm of patients planned for liver transplantation, resection, or ablation may improve outcomes.

Prognostic factors for hepatocellular carcinoma recurrence

The recurrence of hepatocellular carcinoma, the sixth most common neoplasm and the third leading cause of cancer-related mortality worldwide, represents an important clinical problem, since it may occur after both surgical and medical treatment. The recurrence rate involves 2 phases: an early phase and a late phase. The early phase usually occurs within 2 years after resection; it is mainly related to local invasion and intrahepatic metastases and, therefore, to the intrinsic biology of the tumor. On the other hand, the late phase occurs more than 2 years after surgery and is mainly related to de novo tumor formation as a consequence of the carcinogenic cirrhotic environment. Since recent studies have reported that early and late recurrences may have different risk factors, it is clinically important to recognize these factors in the individual patient as soon as possible. The aim of this review was, therefore, to identify predicting factors for the recurrence of hepatocellular carcinoma, by means of invasive and non-invasive methods, according to the different therapeutic strategies available. In particular the role of emerging techniques (e.g., transient elastography) and biological features of hepatocellular carcinoma in predicting recurrence have been discussed. In particular, invasive methods were differentiated from non-invasive ones for research purposes, taking into consideration the emerging role of the genetic signature of hepatocellular carcinoma in order to better allocate treatment strategies and surveillance follow-up in patients with this type of tumor.

Liver Transplantation for Hepatocellular Carcinoma beyond Milan Criteria: Multidisciplinary Approach to Improve Outcome

The implementation of the Milan criteria (MC) in 1996 has dramatically improved prognosis after liver transplantation (LT) in patients with hepatocellular carcinoma (HCC). Liver transplantation has, thereby, become the standard therapy for patients with "early-stage" HCC on liver cirrhosis. The MC were consequently adopted by United Network of Organ Sharing (UNOS) and Eurotransplant for prioritization of patients with HCC. Recent advancements in the knowledge about tumor biology, radiographic imaging techniques, locoregional interventional treatments, and immunosuppressive medications have raised a critical discussion, if the MC might be too restrictive and unjustified keeping away many patients from potentially curative LT. Numerous transplant groups have, therefore, increasingly focussed on a stepwise expansion of selection criteria, mainly based on tumor macromorphology, such as size and number of HCC nodules. Against the background of a dramatic shortage of donor organs, however, simple expansion of tumor macromorphology may not be appropriate to create a safe extended criteria system. In contrast, rather the implementation of reliable prognostic parameters of tumor biology into selection process prior to LT is mandatory. Furthermore, a multidisciplinary approach of pre-, peri-, and posttransplant modulating of the tumor and/or the patient has to be established for improving prognosis in this special subset of patients.

18F-FDG PET and combined 18F-FDG-contrast CT parameters as predictors of tumor control for hepatocellular carcinoma after stereotactic ablative radiotherapy

The application of stereotactic ablative radiotherapy (SABR) to hepatocellular carcinoma (HCC) is emerging. To identify pretreatment prognostic indicators is crucial for patient selection and optimal individual therapy. The aim of this study was to determine whether (18)F-FDG PET and a combined (18)F-FDG-contrast CT parameter could be useful tools to predict tumor control for patients with HCC treated by SABR.

METHODS

We retrospectively identified 31 patients (41 tumors) who underwent (18)F-FDG PET before SABR between November 2007 and September 2011. (18)F-FDG PET parameters were collected as prognostic indicators, including visual PET scale (+/-), maximal standardized uptake value (SUV) of the tumor (T SUV max), ratio of T SUV max to maximal normal-liver SUV, ratio of T SUV max to mean normal-liver SUV, and score combining tumor volume and T SUV max (CT/(18)F-FDG PET score). They underwent SABR with a median dose of 42 Gy (ranging from 30 to 50 Gy) in 4-5 fractions. (18)F-FDG PET parameters and clinical factors were tested as predictors of tumor control and patient survival.

RESULTS

The median follow-up time was 18 mo. Among the parameters examined, T SUV max and CT/(18)F-FDG PET score were significantly correlated with tumor control. T SUV max with a cutoff value of 3.2 was the most significant prognostic indicator. The 4-y control rate was 86.2% in tumors with a T SUV max of 3.2 or less but only 37.5% in those with a T SUV max of more than 3.2 (adjusted hazard ratio, 9.40; 95% confidence interval, 1.18-74.76; P = 0.034). CT/(18)F-FDG PET score (≤ 4 vs. >4) was also a significant predictor of tumor control after SABR. Tumors with a CT/(18)F-FDG PET score of more than 4 had a 5.23-fold risk of tumor failure. After adjustment for factors of sex, American Joint Committee on Cancer stage, Cancer of the Liver Italian Program score, and Child-Pugh classification, tumors with a score of more than 4 had a 4.96-fold risk of failure after SABR, compared with tumors with a score of 4 or less. For overall survival, none was statistically significant.

CONCLUSION

The use of (18)F FDG PET to predict tumor control is feasible. T SUV max with a cutoff value of 3.2 is the best prognostic indicator. We suggest that (18)F-FDG PET may be a reference for prognostic prediction, patient selection, and radiation dose adjustment for HCC patients treated with SABR.

Extended postinterventional tumor necrosis-implication for outcome in liver transplant patients with advanced HCC

Background

Locoregional interventional bridging therapy (IBT) is an accepted neoadjuvant approach in liver transplant candidates with hepatocellular carcinoma (HCC). However, the prognostic value of IBT in patients with advanced HCC is still undefined.

Aim

The aim of this trial was to evaluate the impact of postinterventional tumor necrosis on recurrence-free long-term survival after liver transplantation (LT) in patients with HCC, especially focusing on those exceeding the Milan criteria on pretransplant radiographic imaging.

Patients and Methods

A total of 93 consecutive liver transplant candidates with HCC were included in this trial. In 36 patients, tumors were clinically staged beyond Milan criteria prior LT. Fifty-nine patients underwent IBT by transarterial chemoembolization or radiofrequency ablation pretransplantation. Postinterventional tumor necrosis rate as assessed at liver explant pathology was correlated with outcome post-LT.

Results

There was no significant difference in 5-year tumor-free survival rate between the IBT- and the non-IBT subpopulation (78% versus 68%, P = 0.25). However, tumor response following IBT (≥50% tumor necrosis rate at explant pathology) resulted in a significantly better outcome 5 years post-LT (96%) than tumor non-response to IBT (<50% tumor necrosis rate at explant pathology; 21%; P<0.001). Five-year recurrence-free survival rate was 80% in Milan Out patients with extended post-IBT tumor necrosis versus 0% in Milan Out patients without tumor response to IBT (P<0.001). None of macromorphological HCC features, but only the absence of increased ¹⁸F-fluoro-deoxy-glucose (¹⁸FDG) uptake on pretransplant positron emission tomography (PET) was identified as independent predictor of postinterventional tumor response (P<0.001).

Conclusion

Our results implicate that extended postinterventional tumor necrosis promotes recurrence-free long-term survival in patients with HCC beyond standard criteria. Pretransplant PET assessment may identify those patients with advanced HCC that will benefit from post-IBT tumor response and may, thereby, achieve excellent posttransplant outcome.

Predictive value of 18F-fluorodeoxyglucose PET/CT for transarterial chemolipiodolization of hepatocellular carcinoma

AIM: To investigate the correlation of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) with clinical features and the prediction of treatment response.

METHODS: A total of 83 hepatocellular carcinoma (HCC) patients undergoing ¹⁸F-FDG PET before transarterial chemolipiodolization with systemic chemo-infusion between October, 2006 and May, 2009 were retrospectively enrolled. The patients included 68 men and 15 women (mean age, 60 ± 10.7 years). The effect of ¹⁸F-FDG-monitored PET uptake on clinical features and on the evaluated treatment response was ascertained with modified Response Evaluation Criteria in Solid Tumors. The PET parameters of maximal standardized uptake value of the tumor (Tsuv_max), the ratio of the tumor maximal standardized uptake value (SUV) to the liver maximal SUV (Tsuv_max/Lsuv_max) and the ratio of tumor maximal SUV to the liver mean SUV (Tsuv_max/Lsuv_mean) were tested as predictive factors.

RESULTS: Among the 3 SUV parameters, the Tsuv_max/Lsuv_mean ratio (cutoff value of 1.90) was significantly associated with tumor burden including tumor size, tumor number, α-fetoprotein levels and tumor stage (P < 0.001, P = 0.008, P = 0.011, P < 0.001, respectively). The objective response rates in patients with a high SUV ratio (≥ 1.90) were significantly better than those with a low SUV ratio (< 1.90) (P = 0.020). The overall survival rates of patients exhibiting a low Tsuv_max/Lsuv_mean ratio (< 1.90) and those with a high SUV ratio (≥ 1.90) was 38.2 and 10.3 mo, respectively (P < 0.01). However, the time to progression showed no significant difference between the groups (P = 0.15).

CONCLUSION: ¹⁸F-FDG PET can be an important predictor of HCC treatment. In particular, the Tsuv_max/Lsuv_mean ratio (cutoff value of 1.90) can provide useful information in treatment prognosis for HCC patients treated with locoregional therapy.

Bilateral breast uptake demonstrated on FDG PET/CT scans in 3 male patients with hepatocellular carcinomas

We reported 3 male patients with hepatocellular carcinoma who underwent FDG PET/CT for systemic survey before liver transplantation. All of their scans demonstrated obvious FDG uptake in bilateral breasts. These uptakes might be owing to gynecomastia caused by an increase in free estrogen related to the cirrhotic liver.

F-18 FDG in conjunction with 11C-choline PET/CT in the diagnosis of hepatocellular carcinoma

PURPOSE

F-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET)/computed tomography (CT) alone has limited sensitivity for the diagnosis of hepatocellular carcinoma (HCC). We hoped to improve the diagnostic sensitivity by combining F-18 FDG and C-choline PET/CT.

MATERIALS AND METHODS

A total of 76 consecutive patients with HCC were prospectively enrolled. Whole-body F-18 FDG PET/CT scan was performed for all patients. In those patients with negative F-18 FDG scans, a regional C-choline PET/CT scan was also performed.

RESULTS

Positive F-18 FDG scans were noted in 61.1% (48/76) patients with HCC. Increased F-18 FDG uptake correlated with decreased tumor differentiation (P = 0.042). In 28 HCC patients with negative F-18 FDG scans, C-choline scan was positive in 71.4% patients. C-choline scan did not detect any significant difference between well- and moderately differentiated HCC (P = 0.585). Compared with F-18 FDG scan, C-choline scan showed a trend toward an improved detection of well-differentiated HCC (66.7% vs. 35.7%, NS). For detection of moderately differentiated HCC, the sensitivity of C-choline and F-18 FDG PET/CT was similar (85.7% vs. 72.0%, P = 0.648). The dual-tracer modality improved the diagnostic sensitivity of F-18 FDG PET/CT alone from 63.1% to 89.5% (P < 0.001).

CONCLUSIONS

F-18 FDG in conjunction with C-choline increases the sensitivity of PET/CT in detecting HCC.

Should a radiological diagnosis of hepatocellular carcinoma be routinely confirmed by a biopsy? No

Modern multiphase diagnostic imaging allows diagnosis of hepatocellular carcinoma with high specificity in a large proportion of cases. Additional aspects of tumor biology also can be evaluated noninvasively through observation of tumor behavior (growth rate, satellites, vascular invasion) and other indicators of tumor biology (avid uptake of fluorodeoxyglucose, high circulating levels of tumor markers such as alphafetoprotein). Routinely requiring biopsy confirmation for diagnosis of HCC exposes many patients to unnecessary risk, may delay diagnosis, and in some cases leads to withholding of potentially beneficial treatment. Biopsy for assessment of tumor molecular markers is promising but remains investigational. When diagnosis of HCC is clinically evident by imaging criteria, tumor biopsy should not be required prior to initiating treatment.

Application of positron emission tomography molecular probes in hepatocellular carcinoma biological imaging

Biological behavior is a hot issue in hepatocellular carcinoma (HCC) study. Positron emission tomography (PET), a biological imaging technique, has been widely applied in many types of tumors. It is capable of noninvasive detection of biological behavior. Different radiotracers provide different information of HCC, including glucose/lipid metabolism, DNA synthesis, and apoptosis. In addition, radiotracer uptake relates to biological and clinical prognostic markers. In this article we review the application of several existing and novel radiotracers in PET in HCC study.

Contribution of biomarkers and imaging in the management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most frequent malignant tumour of the liver. HCC prognosis is dependent on the determination of the tumour stage by conventional imaging and early screening. However, patient survival can vary with the same tumour stage. Biomarkers thus have a role in providing an earlier diagnosis, better prognosis classification before treatment and classification prognosis during treatment. In this review article, we will provide a successive, detailed description of the serum, pathological, molecular and imaging markers of HCC.

Liver transplantation for hepatocellular carcinoma: an update

BACKGROUND

Hepatocellular carcinoma (HCC) is a heterogeneous malignancy with multiple etiologies, high incidence, and high mortality. The standard surgical management for patients with HCC consists of locoregional ablation, surgical resection, or liver transplantation, depending on the background state of the liver. Eighty percent of patients initially presenting with HCC are unresectable, either due to the extent of tumor or the level of underlying hepatic dysfunction. While in patients with no evidence of cirrhosis and good hepatic function resection has been the surgical treatment of choice, it is contraindicated in patients with moderate to severe cirrhosis. Liver transplantation is the optimal surgical treatment.

DATA SOURCES

PubMed search of recent articles (from January 2000 to March 2011) was performed looking for relevant articles about hepatocellular carcinoma and its treatment. Additional articles were identified by evaluating references from selected articles.

RESULTS

Here we review criteria for transplantation, the types, indications, and role of locoregional therapy in treating the cancer and in downstaging for possible later transplantation. We also summarize the contribution of immunosuppression and adjuvant chemotherapy in the management and prevention of HCC recurrence. Finally we discuss recent advances in imaging, tumor biology, and genomics as we delineate the remaining challenges for the diagnosis and treatment of this disease.

CONCLUSIONS

Much can be improved in the diagnosis and treatment of HCC. A great challenge will be to improve patient selection to criteria based on tumor biology. Another will be to incorporate systemic agents post-operatively in patients at high risk for recurrence, paying close attention to efficacy and safety. The future direction of the effort in treating HCC will be to stimulate prospective trials, develop molecular imaging of lymphovascular invasion, to improve recipient selection, and to investigate biomarkers of tumor biology.

PET-CT scan is a valuable modality in the diagnosis of fibrolamellar hepatocellular carcinoma: a case report and a summary of recent literature

We report a case of liver cancer with features consistent with fibrolamellar hepatocellular carcinoma (FLHCC) detected by PET-CT scan. A 20-year-old female with a large liver tumor was diagnosed with 'malignant hepatic tumor' 2 years earlier and received five courses of transhepatic arterial chemoembolization (TACE) before she presented to our hospital with abdominal distension and mild pain at the right upper quadrant. Ultrasound and CT scan showed a large tumor in the right lobe of the liver. Contrast CT scan and (18)F-FDG PET-CT showed metastatic lesions in multiple organs. The imaging diagnosis was confirmed by an ultrasound-guided fine needle biopsy of the hepatic lesion which showed features of FLHCC. Immunohistochemical staining showed a marked increase in the expressions of Hepar, CD99, MIB1, proliferating cell nuclear antigen (PCNA), Fibronectin, E-cadherin and CK7. The recent knowledge on the FLHCC and the possible applications of PET-CT were discussed.

18F-fluorodeoxyglucose uptake on positron emission tomography as a prognostic predictor in locally advanced hepatocellular carcinoma

BACKGROUND

Metabolic activity assessed by (18)F-fluorodeoxyglocuse-positron emission tomography ((18)F-FDG-PET) reflects biological aggressiveness and prognoses in various tumors. The authors present a correlation between tumor metabolic activity and clinical outcomes in patients with hepatocellular carcinoma (HCC).

METHODS

Over a 3-year period (2005-2008), 135 locally advanced HCC patients were treated with localized concurrent chemoradiotherapy (CCRT; external beam radiotherapy at 45 grays for 5 weeks plus concurrent hepatic arterial infusion of 5-fluorouracil during the first and fifth week) followed by repetitive hepatic arterial infusional chemotherapy with 5-fluorouracil and cisplatin. Among them, the authors studied 107 who received (18)F-FDG-PET before CCRT. Maximal standardized uptake values (SUVs) of tumors were calculated.

RESULTS

The median maximal tumor SUV was 6.1 (range, 2.4-∼19.2). Patients with low maximal tumor SUVs (<6.1) had a higher disease control rate than those with high maximal tumor SUVs (≥6.1) (86.8% vs 68.5%, respectively, P = .023). Both median progression-free survival (PFS; 8.4 vs 5.2 months; P = .003) and overall survival (OS; 17.9 vs 11.3 months; P = .013) were significantly longer in the low maximal tumor SUV group than in the high maximal tumor SUV group, respectively. In multivariate analysis, low maximal tumor SUV and objective responses to CCRT remained significant for PFS and OS. The high maximal tumor SUV group was more likely to have extrahepatic metastasis within 6 months than the low maximal tumor SUV group (58.1% vs 26.8%, respectively; P < .001). Similar results were obtained for the maximal tumor SUV/normal liver maximal SUV ratio (<2 vs ≥2) concerning progression, death, and extrahepatic metastasis.

CONCLUSIONS

Metabolic activity may be useful not only in predicting prognosis and treatment responses, but also in establishing optimal treatment plans in locally advanced HCC.

[Hepatocellular carcinoma and cholangiocarcinoma]

Hepatocellular carcinoma and cholangiocarcinoma are relatively rare tumors of the gastrointestinal tract in western Europe but their incidence has been increased in recent years. Newly diagnosed intrahepatic lesions or intrahepatic cholestasis require extensive laboratory tests and imaging studies in order to confirm the diagnosis of hepatocellular carcinoma, intrahepatic or extrahepatic cholangiocarcinoma. The treatment options range from liver resection or liver transplantation to conservative measures (in cases of non-resectable lesions). This review article aims to provide an overview on the diagnostic options and the subsequent treatment.