The prognostic value of 18F-FDG PET/CT for hepatocellular carcinoma treated with transarterial chemoembolization (TACE)

An interpretable machine learning model based on contrast-enhanced CT parameters for predicting treatment response to conventional transarterial chemoembolization in patients with hepatocellular carcinoma

OBJECTIVE

To explore the potential of pre-therapy computed tomography (CT) parameters in predicting the treatment response to initial conventional TACE (cTACE) in intermediate-stage hepatocellular carcinoma (HCC) and develop an interpretable machine learning model.

METHODS

This retrospective study included 367 patients with intermediate-stage HCC who received cTACE as first-line therapy from three centers. We measured the mean attenuation values of target lesions on multi-phase contrast-enhanced CT and further calculated three CT parameters, including arterial (AER), portal venous (PER), and arterial portal venous (APR) enhancement ratios. We used logistic regression analysis to select discriminative features and trained three machine learning models via 5-fold cross-validation. The performance in predicting treatment response was evaluated in terms of discrimination, calibration, and clinical utility. Afterward, a Shapley additive explanation (SHAP) algorithm was leveraged to interpret the outputs of the best-performing model.

RESULTS

The mean diameter, ECOG performance status, and cirrhosis were the important clinical predictors of cTACE treatment response, by multiple logistic regression. Adding the CT parameters to clinical variables showed significant improvement in performance (net reclassification index, 0.318, P < 0.001). The Random Forest model (hereafter, RF-combined model) integrating CT parameters and clinical variables demonstrated the highest performance on external validation dataset (AUC of 0.800). The decision curve analysis illustrated the optimal clinical benefits of RF-combined model. This model could successfully stratify patients into responders and non-responders with distinct survival (P = 0.001).

CONCLUSION

The RF-combined model can serve as a robust and interpretable tool to identify the appropriate crowd for cTACE sessions, sparing patients from receiving ineffective and unnecessary treatments.

Emulsifying Lipiodol with pH-sensitive DOX@HmA nanoparticles for hepatocellular carcinoma TACE treatment eliminate metastasis

Lipiodol-based transcatheter arterial chemoembolization (TACE) is currently the predominant and first-line treatment option recommended by the global standard for unresectable hepatocellular carcinoma (HCC). However, the unstable emulsion of Lipiodol causes a substantial proportion of chemotherapy drugs to enter the circulation system, leading to poor accumulation in cancer tissues and unexpected side effects of chemotherapy drugs. Herein, we emulsified Lipiodol with a pH-sensitive drug delivery system assembled from hexahistidine and zinc ions (HmA) with a super-high loading capacity of doxorubicin (DOX) and a promising ability to penetrate bio-barriers for the effective treatment of HCC by TACE. In vitro tests showed that DOX@HmA was comparable to free DOX in killing HCC cells. Impressively, during the in vivo TACE treatment, the anti-tumor efficacy of DOX@HmA was significantly greater than that of free DOX, indicating that DOX@HmA increased the accumulation of DOX in tumor. Emulsifying Lipiodol with pH-sensitive DOX@HmA significantly inhibited cell regeneration and tumor angiogenesis and decreased the systemic side effects of chemotherapy, especially by suppressing pulmonary metastasis in liver VX2 tumors in rabbits by inhibiting epithelial-mesenchymal transition (EMT). Emulsifying tumor microenvironment-responsive drug delivery systems (DDSs) with Lipiodol could be a new strategy for clinical TACE chemotherapy with potentially enhanced HCC treatment.

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.

Idarubicin-loaded biodegradable microspheres enhance sensitivity to anti-PD1 immunotherapy in transcatheter arterial chemoembolization of hepatocellular carcinoma

Transarterial chemoembolization (TACE) is an image-guided locoregional therapy used for the treatment of patients with primary hepatocellular carcinoma (HCC). However, conventional TACE formulations such as epirubicin-lipiodol emulsion are rapidly dissociated due to the instability of the emulsion, resulting in insufficient local drug concentrations in the target tumor. To overcome these limitations, we used biodegradable Idarubicin loaded microspheres (BILMs), which were prepared from gelatin and carrageenan and could be loaded with Idarubicin (IDA-MS). The morphology and the ability to load and release IDA of BILMs were characterized in vitro. We evaluated tumor changes and side effects after TACE treatment with IDA-MS in VX2 rabbit and C57BL/6 mice HCC models. In addition, the effect of IDA-MS on the tumor immune microenvironment of HCC tumors was elucidated via mass spectrometry and immunohistochemistry. Result showed that IDA-MS was developed as a new TACE formulation to overcome the poor delivery of drugs due to rapid elimination of the anticancer drug into the systemic circulation. We demonstrated in rabbits and mice HCC models that TACE with IDA-MS resulted in significant tumor shrinkage and no more severe adverse events than those observed in the IDA group. TACE with IDA-MS could also significantly enhance the sensitivity of anti-PD1 immunotherapy, improve the expression of CD8⁺ T cells, and activate the tumor immune microenvironment in HCC. This study provides a new approach for TACE therapy and immunotherapy and illuminates the future of HCC treatment. STATEMENT OF SIGNIFICANCE: Conventional transarterial chemoembolization (TACE) formulations are rapidly dissociated due to the instability of the emulsion, resulting in insufficient local drug concentrations in hepatocellular carcinoma (HCC). To overcome these limitations, we used biodegradable microspheres called BILMs, which could be loaded with Idarubicin (IDA-MS). We demonstrated in rabbits and mice HCC models that TACE with IDA-MS resulted in significant tumor shrinkage and no more severe adverse events than those observed in the IDA group. TACE with IDA-MS could also significantly enhance the sensitivity of anti-PD1 immunotherapy, improve the expression of CD8⁺ T cells, and activate the tumor immune microenvironment in HCC. This study provides a new approach for TACE therapy and immunotherapy and illuminates the future of HCC treatment.

18F-Fluorodeoxyglucose-PET-Computerized Tomography and non-Fluorodeoxyglucose PET-Computerized Tomography in Hepatobiliary and Pancreatic Malignancies

Molecular imaging with PET-computerized tomography (PET-CT) plays an important role in oncology. There is current and evolving evidence supporting the use of fluorodeoxyglucose (FDG) and non-FDG tracers in assessment patients with hepatobiliary and pancreatic cancers in various clinical scenarios. In this chapter, we discuss the advantages and limitations of FDG and non-FDG PET-CT in the management of patients with hepatobiliary and pancreatic cancers.

Intraarterial contrast-enhanced ultrasound to predict the short-term tumour response of hepatocellular carcinoma to Transarterial chemoembolization with Lipiodol

BACKGROUND

Transarterial chemoembolization (TACE) is an effective locoregional therapy in hepatocellular carcinoma (HCC). However, it is difficult to predict the tumour response (TR) of TACE intraprocedurally. The aim of this study was to predict the TR after TACE (1-3 months) in HCC patients using intraprocedural intraarterial contrast enhanced ultrasound (IA-CEUS).

METHODS

In this case-control study, consecutive patients who received TACE in our hospital from September 2018 to May 2019 were enrolled. IA-CEUS was performed before and after TACE. Postoperative contrast-enhanced liver MRI was performed 1-3 months after TACE as the gold standard. According to the modified Response Evaluation Criteria in Solid Tumours (mRECIST), ultrasonic manifestations were compared between the complete remission (CR) group and non-CR group by univariate and multivariate analyses. A logistic predictive model was established and validated, and its diagnostic efficiency was evaluated.

RESULTS

Forty-four patients with sixty-one lesions were enrolled in the study. Multivariate analysis identified, the risk factors as a large lesion diameter (OR: 1.84; 95% confidence interval [CI]: 1.009, 3.080; P = 0.020), a larger dimension of non-enhancing area in superior mesenteric artery (SMA)-CEUS than the size in B-mode ultrasound preoperatively (OR: 3.379; 95% CI: 1.346,8.484; P = 0.010), presence of corona enhancement in hepatic artery (HA)-CEUS postoperatively (OR: 6.642; 95% CI: 1.214, 36.331; P = 0.029), and decreased corona enhancement thickness (per centimetre) postoperatively (OR: 0.025; 95% CI: 0.006,0.718; P = 0.025). The area under the receiver operating characteristic curve (AUROC) of the predictive model was 0.904 (95% CI: 0.804, 0.966; P < 0.001). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 81.08, 91.67, 85.25, 93.75, and 75.86%, respectively. Leave-one-out cross-validation (LOOCV) showed that the accuracy was 77.05%.

CONCLUSIONS

Intraprocedural IA-CEUS can be used to predict the TR in HCC patients after TACE.

Development and evaluation of an ultrasound-triggered microbubble combined transarterial chemoembolization (TACE) formulation on rabbit VX2 liver cancer model

Transarterial chemoembolization (TACE) is an image-guided locoregional therapy used for the treatment of patients with primary or secondary liver cancer. However, conventional TACE formulations are rapidly dissociated due to the instability of the emulsion, resulting in insufficient local drug concentrations in the target tumor.

Methods: To overcome these limitations, a doxorubicin-loaded albumin nanoparticle-conjugated microbubble complex in an iodized oil emulsion (DOX-NPs-MB complex in Lipiodol) has been developed as a new ultrasound-triggered TACE formulation.

Results: (1) Microbubbles enhanced therapeutic efficacy by effectively delivering doxorubicin- loaded nanoparticles into liver tumors via sonoporation under ultrasound irradiation (US+). (2) Microbubbles constituting the complex retained their function as an ultrasound contrast agent in Lipiodol. In a rabbit VX2 liver cancer model, the in vivo study of DOX-NPs-MB complex in Lipiodol (US+) decreased the viability of tumor more than the conventional TACE formulation, and in particular, effectively killed cancer cells in the tumor periphery.

Conclusion: Incorporation of doxorubicin-loaded microbubble in the TACE formulation facilitated drug delivery to the tumor with real-time monitoring and enhanced the therapeutic efficacy of TACE. Thus, the enhanced TACE formulation may represent a new treatment strategy against liver cancer.

Role of 18-FDG/PET in evaluation of hepatocellular carcinoma managed locally by transarterial chemoembolization compared to triphasic computed tomography

Background

This study was done to evaluate the role of FDG/PET compared to CECT in evaluating HCC after local interventional treatment. We evaluate forty-six patients with known history of TACE as a locoregional treatment of pathologically proved HCC. There were forty-three males and three females.

Results

The collected data were statistically analyzed, and we found that FDG-PET has a sensitivity of 94%, specificity of 84%, positive predictive value of 86.7%, negative predictive value of 86.4%, and accuracy of 93.4% in the detection of residual or recurrent at the managed tumor bed compared to CECT which shows a sensitivity of 94%, specificity of 84%, positive predictive value of 86.7%, negative predictive value of 86.4%, and accuracy of 93.4 %). Combined views ( FDG-PET/CT ) are better in evaluation.

Conclusion

FDG-PET is better in the detection of residual or recurrence in HCC which is locally managed by TACE.

Hepatic Arterial Bland Embolization Increases Th17 Cell Infiltration in a Syngeneic Rat Model of Hepatocellular Carcinoma

PURPOSE

To determine the tumor immune cell landscape after transcatheter arterial bland embolization (TAE) in a clinically relevant rat hepatocellular carcinoma (HCC) model.

MATERIALS AND METHODS

Buffalo rats (n = 21) bearing syngeneic McArdle RH-7777 rat hepatoma cells implanted into the left hepatic lobe underwent TAE using 70-150 µm beads (n = 9) or hepatic artery saline infusion (n = 12). HCC nodules, peritumoral margin, adjacent non-cancerous liver, and splenic parenchyma were collected and disaggregated to generate single-cell suspensions for immunological characterization 14 d after treatment. Changes in tumor-infiltrating immune subsets including CD4 T cells (Th17 and Treg), CD8 cytotoxic T cells (IFNγ), and neutrophils were evaluated by multiparameter flow cytometry. Migration and colony formation assays were performed to examine the effect of IL-17, a signature cytokine of Th17 cells, on McArdle RH-7777 hepatoma cells under conditions simulating post-embolization environment (i.e., hypoxia and nutrient privation). Statistical significance was determined by the Student unpaired t test or one-way ANOVA.

RESULTS

TAE induces increased infiltration of Th17 cells in liver tumors when compared with controls 14 d after treatment (0.29 ± 0.01 vs. 0.19 ± 0.02; p = 0.02). A similar pattern was observed in the spleen (1.41 ± 0.13 vs. 0.57 ± 0.08; p < 0.001), indicating both local and systemic effect. No significant differences in the percentage of FoxP3 + Tregs, IFNγ-producing CD4 T cells, and CD8 T cells were observed between groups (p > 0.05). In vitro post-embolization assays demonstrated that IL-17 reduces McA-RH7777 cell migration at 24-48 h (p = 0.003 and p = 0.002, respectively).

CONCLUSION

Transcatheter hepatic arterial bland embolization induces local and systemic increased infiltration of Th17 cells and expression of their signature cytokine IL-17. In a simulated post-embolization environment, IL-17 significantly reduced McA-RH7777 cell migration.

Emerging role of 18F-fluorodeoxyglucose positron emission tomography for guiding management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of major causes of cancer mortality worldwide. For decades, ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been widely used for staging, predicting prognosis, and detecting cancer recurrence in various types of malignant diseases. Due to low sensitivity of FDG PET for detecting intrahepatic HCC lesions, the clinical value of FDG PET in HCC patients has been limited. However, recent studies with diverse analytic methods have shown that FDG PET has promising role in aiding management of HCC patients. In this review, we will discuss the clinical role of FDG PET for staging, predicting prognosis, and evaluating treatment response in HCC. Further, we will focus on recent clinical studies regarding implication of volumetric FDG PET parameters, the significance of FDG uptake in HCC for selecting treatment and predicting treatment response, and the use of radiomics of FDG PET in HCC.

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 interplay of circulating tumor DNA and chromatin modification, therapeutic resistance, and metastasis

Peripheral circulating free DNA (cfDNA) is DNA that is detected in plasma or serum fluid with a cell-free status. For cancer patients, cfDNA not only originates from apoptotic cells but also from necrotic tumor cells and disseminated tumor cells that have escaped into the blood during epithelial-mesenchymal transition. Additionally, cfDNA derived from tumors, also known as circulating tumor DNA (ctDNA), carries tumor-associated genetic and epigenetic changes in cancer patients, which makes ctDNA a potential biomarker for the early diagnosis of tumors, monitory and therapeutic evaluations, and prognostic assessments, among others, for various kinds of cancer. Moreover, analyses of cfDNA chromatin modifications can reflect the heterogeneity of tumors and have potential for predicting tumor drug resistance.

Joint Consensus Statement of the Indian National Association for Study of the Liver and Indian Radiological and Imaging Association for the Diagnosis and Imaging of Hepatocellular Carcinoma Incorporating Liver Imaging Reporting and Data System

Hepatocellular carcinoma (HCC) is the 6th most common cancer and the second most common cause of cancer-related mortality worldwide. There are currently no universally accepted practice guidelines for the diagnosis of HCC on imaging owing to the regional differences in epidemiology, target population, diagnostic imaging modalities, and staging and transplant eligibility. Currently available regional and national guidelines include those from the American Association for the Study of Liver Disease (AASLD), the European Association for the Study of the Liver (EASL), the Asian Pacific Association for the Study of the Liver, the Japan Society of Hepatology, the Korean Liver Cancer Study Group, Hong Kong, and the National Comprehensive Cancer Network in the United States. India with its large population and a diverse health infrastructure faces challenges unique to its population in diagnosing HCC. Recently, American Association have introduced a Liver Imaging Reporting and Data System (LIRADS, version 2017, 2018) as an attempt to standardize the acquisition, interpretation, and reporting of liver lesions on imaging and hence improve the coherence between radiologists and clinicians and provide guidance for the management of HCC. The aim of the present consensus was to find a common ground in reporting and interpreting liver lesions pertaining to HCC on imaging keeping LIRADSv2018 in mind.

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

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

Imaging Hepatocellular Carcinoma With 68Ga-Citrate PET: First Clinical Experience

While cross-sectional imaging with computed tomography (CT) and magnetic resonance imaging is the primary method for diagnosing hepatocellular carcinoma (HCC), they provide little biological insight into this molecularly heterogeneous disease. Nuclear imaging tools that can detect molecular subsets of tumors could greatly improve diagnosis and management of HCC. To this end, we conducted a patient study to determine whether HCC can be resolved using ⁶⁸Ga-citrate positron emission tomography (PET). One patient with recurrent HCC was injected with 300 MBq of ⁶⁸Ga-citrate and imaged with PET/CT 249 minutes post injection. Four (28%) of 14 hepatic lesions were avid for ⁶⁸Ga-citrate. One extrahepatic lesion was not PET avid. The average maximum standardized uptake value (SUV_max) for the lesions was 7.2 (range: 6.2-8.4), while the SUV_max of the normal liver parenchyma was 4.7 and blood pool was 5.7. The avid lesions were not significantly larger than the quiescent lesions, and a prior contrast CT showed uniform enhancement among the lesions, suggesting that tumor signals are due to specific binding of the radiotracer to the transferrin receptor, rather than enhanced vascularity in the tumor microenvironment. Further studies are required in a larger patient cohort to verify the molecular basis of radiotracer uptake and the clinical utility of this tool.

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.

Prognostic Value of Metabolic Parameters of 18F-FDG PET/CT and Apparent Diffusion Coefficient of MRI in Hepatocellular Carcinoma

BACKGROUND

The aim of this study was to predict the survival of patients with hepatocellular carcinoma (HCC) by examining metabolic PET parameters, apparent diffusion coefficients (ADCs), and clinical parameters.

METHODS

We retrospectively reviewed 52 patients with pathologically confirmed HCC (age, 57.9 ± 10.7 years; 43 men) who underwent MRI and F-FDG PET/CT. The tumor-to-normal liver SUV ratio (TLR), the mean ADC of each tumor, and other clinical data were obtained. Survival analysis was performed.

RESULTS

Thirty-two patients died during the follow-up period. There was an inverse correlation between the mean SUV and the mean ADC of a tumor (r = -0.402, P = 0.020). Among HCC patients, disease-specific survival was significantly associated with each of the following factors: high TLR (TLR ≥ 2; hazard ratio [HR], 3.78; P = 0.001), high mean ADC (mean ADC ≥ 1.250 × 10 mm/s; HR, 0.45; P = 0.028), AFP ≥ 400 ng/mL (HR, 3.48; P = 0.001), PIVKA-II ≥ 100mAU/mL (HR, 6.39; P = 0.011), tumor size (HR, 1.13; P < 0.001), number of tumors (HR, 2.16; P = 0.031), tumor stage (HR, 3.08; P < 0.001), and surgery for initial treatment (HR, 0.06; P < 0.001). The results of multivariate analysis show that DSS was significantly associated with each of the following factors: TLR ≥ 2 (HR, 2.46; P = 0.044), PIVKA-II ≥ 100mAU/mL (HR, 5.11; P = 0.037), tumor stage (HR, 3.01; P < 0.001), and surgery for initial treatment (HR, 0.04; P < 0.001).

CONCLUSIONS

High TLRs and low mean ADCs were associated with poor outcomes. The TLR was an independent prognostic factor in patients with HCC, but the mean ADC was not. A negative correlation was found between the mean ADC and the mean SUV of a tumor.

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

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

Hepatic imaging following intra-arterial embolotherapy

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prognostic value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with Barcelona Clinic Liver Cancer stages 0 and A hepatocellular carcinomas: a multicenter retrospective cohort study

PURPOSE

We evaluated the prognostic value of pretreatment (18)F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET/CT) in patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 or A hepatocellular carcinoma (HCC) who had received curative treatment or transarterial chemoembolization (TACE).

METHODS

Between 2009 and 2010, 317 patients diagnosed with HCC at seven hospitals were enrolled. Among these, 195 patients underwent curative treatments including resection, liver transplantation, and radiofrequency ablation. TACE was performed in 122 patients. The tumor-to-normal liver standardized uptake value ratio (TLR) of the primary tumor was measured using pretreatment FDG PET/CT. The prognostic significance of TLR and other clinical variables was assessed using Cox regression models. Differences in the overall survival (OS) associated with TLR or other significant clinical factors were examined using the Kaplan-Meier method.

RESULTS

Over a median follow-up period of 46 months, 77 patients died from cancer. In the curative cohort, higher TLR (≥2) was significantly associated with death (hazard ratio [HR] = 2.68; 95 % CI, 1.16-6.15; P = 0.020) in multivariable analysis. Patients with a higher TLR had significantly worse OS than patients with a lower TLR (5-year overall survival, 61 % vs. 79.4 %; P = 0.006). In the TACE cohort, the Model for End-Stage Liver Disease (MELD) score (≥8) was a significant independent prognostic factor for OS (HR = 3.34; 95 % CI, 1.49-7.48; P = 0.003), whereas TLR was not associated with OS. The Kaplan-Meier curves showed significantly poorer OS in patients with higher MELD scores (≥8) than in those with lower MELD scores (5-year survival rate, 33.1 % vs. 79.6 %; P < 0.001).

CONCLUSIONS

Pretreatment TLR measured using FDG PET/CT was an independent prognostic factor for OS in patients with BCLC stage 0 or A HCC undergoing curative treatment. In contrast, underlying liver function appeared to be important in predicting the prognosis of patients undergoing TACE.

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.

Lymphatic imaging: focus on imaging probes

In view of the importance of sentinel lymph nodes (SLNs) in tumor staging and patient management, sensitive and accurate imaging of SLNs has been intensively explored. Along with the advance of the imaging technology, various contrast agents have been developed for lymphatic imaging. In this review, the lymph node imaging agents were summarized into three groups: tumor targeting agents, lymphatic targeting agents and lymphatic mapping agents. Tumor targeting agents are used to detect metastatic tumor tissue within LNs, lymphatic targeting agents aim to visualize lymphatic vessels and lymphangionesis, while lymphatic mapping agents are mainly for SLN detection during surgery after local administration. Coupled with various signal emitters, these imaging agents work with single or multiple imaging modalities to provide a valuable way to evaluate the location and metastatic status of SLNs.