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

Hepatocellular Carcinoma: Optimal Radiological Evaluation before Liver Transplantation

Liver transplantation (LT) is the recommended curative-intent treatment for patients with early or intermediate-stage hepatocellular carcinoma (HCC) who are ineligible for resection. Imaging plays a central role in staging and for selecting the best LT candidates. This review will discuss recent developments in pre-LT imaging assessment, in particular LT eligibility criteria on imaging, the technical requirements and the diagnostic performance of imaging for the pre-LT diagnosis of HCC including the recent Liver Imaging Reporting and Data System (LI-RADS) criteria, the evaluation of the response to locoregional therapy, as well as the non-invasive prediction of HCC aggressiveness and its impact on the outcome of LT. We will also briefly discuss the role of nuclear medicine in the pre-LT evaluation and the emerging role of artificial intelligence models in patients with HCC.

The application of 18F-FDG PET/CT imaging for human hepatocellular carcinoma: a narrative review

Background and Objective

Primary hepatocellular carcinoma (HCC) poses a significant threat to human health. The mean overall survival (OS) of HCC is approximately 15.8 months whereas the 6-month and 1-year OS rates are only 71.6% and 49.7%, respectively. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) has been widely used for the management of several solid cancers; however, HCC frequently displays low 18F-FDG uptake; approximately 50% of HCC cases do not take up 18F-FDG. Therefore, 18F-FDG PET is not considered very useful for the visualization of HCC and is not currently a recommended standard imaging modality for HCC. Conversely, 18F-FDG PET/CT has been reported to be clinically important in the management, staging, and prognosis of HCC patients. Currently, reports relating to 18F-FDG uptake in HCC are unclear and controversial. There is an urgent need to clarify the efficacy of 18F-FDG PET for the management of HCC.

Methods

The PubMed database was searched for all articles on the application of 18F-FDG PET/CT imaging for human HCC up to December 2021. The following search terms were used: 'Hepatocellular carcinoma', '[18F]FDG PET/CT', 'Hypoxia', '[11C]Choline'.

Key Content and Findings

In this review, we re-evaluate the potential hypoxia-dependent uptake mechanism of 18F-FDG in HCC and review the usefulness of 18F-FDG PET/CT for identifying, managing, and investigating the biological properties of HCC.

Conclusions

18F-FDG PET/CT is very useful for HCC visualization, management, and the evaluation of biological properties. A negative test for 18F-FDG uptake is not meaningless and may reflect a relatively better outcome. 18F-FDG-positive lesions indicate a significantly less favorable prognosis.

Patient Selection for Downstaging of Hepatocellular Carcinoma Prior to Liver Transplantation—Adjusting the Odds?

Background and Aims: Morphometric features such as the Milan criteria serve as standard criteria for liver transplantation (LT) in patients with hepatocellular carcinoma (HCC). Since it has been recognized that these criteria are too restrictive and do not adequately display the tumor biology, additional selection parameters are emerging.

Methods: Concise review of the current literature on patient selection for downstaging and LT for HCC outside the Milan criteria.

Results: The major task in patients outside the Milan criteria is the need for higher granularity with patient selection, since the benefit through LT is not uniform. The recent literature clearly shows that beneath tumor size and number, additional selection parameters are useful in the process of patient selection for and during downstaging. For initial patient selection, the alpha fetoprotein (AFP) level adds additional information to the size and number of HCC nodules concerning the chance of successful downstaging and LT. This effect is quantifiable using newer selection tools like the WE (West-Eastern) downstaging criteria or the Metroticket 2.0 criteria. Also an initial PET-scan and/or tumor biopsy can be helpful, especially in the high risk group of patients outside the University of California San Francisco (UCSF) criteria. After this entry selection, the clinical course during downstaging procedures concerning the tumor and the AFP response is of paramount importance and serves as an additional final selection tool.

Conclusion: Selection criteria for liver transplantation in HCC patients are becoming more and more sophisticated, but are still imperfect. The implementation of molecular knowledge will hopefully support a more specific risk prediction for HCC patients in the future, but do not provide a profound basis for clinical decision-making at present.

Aggressive behavior of anaplastic undifferentiated carcinoma arising from the hilar bile duct

Background

Undifferentiated carcinoma of the biliary tree is extremely rare, and biliary undifferentiated carcinoma mostly originates from the gallbladder. We herein present a case of anaplastic undifferentiated carcinoma of the hilar bile duct and reviewed the literature.

Case presentation

The patient was an 81-year-old male with obstructive jaundice. Contrast-enhanced computed tomography (CT) showed a protruded tumor located at the hepatic hilum. Obstructive jaundice was relieved by endoscopic drainage. Endoscopic biopsy revealed carcinoma without glandular differentiation, and the patient was diagnosed with resectable hilar undifferentiated carcinoma. During the 5-week preoperative examination, the tumor increased in size from 23 to 45 mm. Left hemi-hepatectomy and extrahepatic bile duct resection were performed, and there were no postoperative complications. Histological findings demonstrated that the tumor was mainly composed of non-cohesive polygonal neoplasms with pleomorphic nuclei, and was diagnosed as anaplastic undifferentiated carcinoma of the common hepatic duct (T2a N0 M0 Stage II). One month after surgery, the patient was readmitted to our hospital with pyrexia due to cholangitis, and liver nodules suggestive of multiple liver metastases were detected by CT. Three months after surgery, the patient died of multiple liver metastases.

Conclusions

This is the first case report of undifferentiated cholangiocarcinoma with anaplastic features. Anaplastic undifferentiated carcinoma of the hilar bile duct showed preoperative rapid growth and early relapse despite a cancer-negative surgical margin.

Noninvasively visualize the expression of LAPTM4B protein using a novel 18F-labeled peptide PET probe in hepatocellular carcinoma

OBJECTIVE

Lysosomal protein transmembrane 4 beta (LAPTM4B) is selectively expressed in hepatocellular carcinoma (HCC) cells and thus a potential biomarker for diagnosing HCC. In this study, we designed a novel ¹⁸F-labeled PET probe to non-invasively visualize LAPTM4B expression in mouse model of HCC tumor.

METHODS

A PET targeting tracer named [¹⁸F]FP-LAP2H was radio-synthesized using a LAPTM4B targeting peptide, LAP2H, coupled with 4-nitrophenyl-2-[¹⁸F]fluoropropionate ([¹⁸F]NFP). Radio-stability, cell uptake, micro PET/CT imaging and ex vivo biodistribution were performed for determining its stability, cell binding specificity, and tumor targeting in vivo.

RESULTS

[¹⁸F]FP-LAP2H was successfully synthesized with radiochemical yields of 6-14% (decay-corrected yield) and molar activity of 10-44 GBq/μmol. The tracer showed stable (~90%) in phosphate-buffered saline, pH 7.4, and in human serum (~80%) for 2 h. In vitro cell uptake studies indicated the radioactivity accumulation in HCC cells was LAPTM4B protein-specific. Micro PET/CT demonstrated that implanted LAPTM4B positive HepG2 and BEL7402 tumors could be clearly visualized. The ex vivo biodistribution studies demonstrated that the tumor/liver ratio were 1.80 ± 0.65 and 2.09 ± 0.68 in implanted HepG2 and BEL7402 tumors respectively. Negative control and blocking experiments revealed that the radioactivity uptake in the HCC tumor was LAPTM4B protein-specific.

CONCLUSIONS

[¹⁸F]FP-LAP2H appears to be a potential PET tracer for imaging LAPTM4B-positive HCC tumor. Further endeavors need to do to improve tumor/liver ratio.

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.

The Role of 18F-FDG PET/MRI in the Assessment of Primary Intrahepatic Neoplasms

RATIONALE AND OBJECTIVES

To evaluate the results of 18F-FDG PET/MRI in relation to the histopathologic subtypes and histologic grades of mass-forming primary intrahepatic neoplasms.

MATERIALS AND METHODS

We retrospectively evaluated 18F-FDG positron emission tomography/magnetic resonance imaging (PET/MRI) results for 39 patients with histopathologically confirmed primary hepatic neoplasms, 15 with mass-forming intrahepatic cholangiocarcinoma (ICC) and 24 with hepatocellular carcinoma (HCC). The apparent diffusion coefficient (ADC) and standardized uptake value (SUV) were analyzed in relation to the histopathologic diagnosis and histologic grade, including calculating the sensitivity and specificity of the imaging findings.

RESULTS

The median SUV of ICC (6.0 [interquartile range, 5-10]) was significantly higher than that of HCC (4.0 [2.62-6.50]) (p = 0.002). An area under the curve (AUC) of 0.79 (95% confidence interval 0.649-0.932) had a sensitivity of 86.7% and a specificity of 67% at the best cut-off SUV of 4.41 to differentiate between ICC and HCC. ADC values did not differ significantly between HCCs and ICCs (p = 0.283). Both SUV and ADC values differed significantly between low-grade (well- and moderately differentiated) and high-grade (poorly differentiated) HCCs. Combining ADC and SUV further improved differentiation of low- from high-grade HCCs to a significant level (0.929). The SUV did not differ significantly between ICC histologic grades (p = 0.280), while the ADC differed significantly only between well and poorly differentiated ICCs (p = 0.004).

CONCLUSION

Assessing primary hepatic neoplasms with 18F-Fluorodeoxyglucose PET/MRI may help to predict tumor grade and differentiate between types of intrahepatic neoplasms.

Liver Transplantation for Hepatocellular Carcinoma: Malatya Experience and Proposals for Expanded Criteria

Survival was examined from a Turkish liver transplant center of patients with HCC, to identify prognostic factors. Data from 215 patients who underwent predominantly live donor liver transplant for HCC at our institute over 12 years were included in the study and prospectively recorded. They were 152 patients within and 63 patients beyond Milan criteria. Patients beyond Milan criteria were divided into two groups according to presence or absence of tumor recurrence. Recurrence-associated factors were analyzed. These factors were then applied to the total cohort for survival analysis. We identified four factors, using multivariate analysis, that were significantly associated with tumor recurrence. These were maximum tumor diameter, degree of tumor differentiation, and serum AFP and GGT levels. A model that included all four of these factors was constructed, the 'Malatya criteria.' Using these Malatya criteria, we estimated DFS and cumulative survival, for patients within and beyond these criteria, and found statistically significant differences with improved survival in patients within Malatya criteria of 1, 5, and 10-year overall survival rates of 90.1%, 79.7%, and 72.8% respectively, which compared favorably with other extra-Milan extended criteria. Survival of our patients within the newly defined Malatya criteria compared favorably with other extra-Milan extended criteria and highlight the usefulness of serum AFP and GGT levels in decision-making.

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.

Intraoperative ultrasound for prediction of hepatocellular carcinoma biological behaviour: Prospective comparison with pathology

BACKGROUND & AIMS

Preoperative prediction of both microinvasive hepatocellular carcinoma and histological grade of hepatocellular carcinoma is pivotal to treatment planning and prognostication. The aim of this study was to evaluate whether some intraoperative ultrasound features correlate with both the presence of same histological patterns and differentiation grade of hepatocellular carcinoma on the histological features of the primary resected tumour.

METHODS

All patients with single, small hepatocellular carcinoma that underwent hepatic resection were included in this prospective double-blind study: the intraoperative ultrasound patterns of nodule were registered and compared with similar histological features.

RESULTS

A total of 179 patients were enclosed in this study: 97 (54%) patients (34% in HCC ≤2 cm) had a microinvasive hepatocellular carcinoma at ultrasound examination, while 82 (46%) patients (41% in HCC ≤2 cm) at histological evaluation. Statistical analysis showed that diameters ≤2 cm, presence of satellites and microinvasive hepatocellular carcinoma at ultrasound examination were the variables with the strongest association with the histological findings. In the multivariate analysis, the vascular microinfiltration and infiltrative hepatocellular carcinoma aspect were independent predictors for grading.

CONCLUSIONS

In patients with cirrhosis and hepatocellular carcinoma, the prevalence of microinvasive hepatocellular carcinoma is high, even in cases of HCC ≤2 cm. Intraoperative ultrasound findings strongly correlated with histopathological criteria in detecting microinvasive patterns and are useful to predict neoplastic differentiation. The knowledge of these features prior to treatment are highly desired (this can be obtained by an intraoperative ultrasound examination), as they could help in providing optimal management of patients with hepatocellular carcinoma.