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

Targeting Hepatic Cancer Stem Cells (CSCs) and Related Drug Resistance by Small Interfering RNA (siRNA)

Tumor recurrence after curative therapy and hepatocellular carcinoma (HCC) cells' resistance to conventional therapies is the reasons for the worse clinical results of HCC patients. A tiny population of cancer cells with a strong potential for self-renewal, differentiation, and tumorigenesis has been identified as cancer stem cells (CSCs). The discovery of CSC surface markers and the separation of CSC subpopulations from HCC cells have been made possible by recent developments in the study of hepatic (liver) CSCs. Hepatic CSC surface markers include epithelial cell adhesion molecules (EpCAM), CD133, CD90, CD13, CD44, OV-6, ALDH, and K19. CSCs have a significant influence on the development of cancer, invasiveness, self-renewal, metastasis, and drug resistance in HCC, and thus provide a therapeutic chance to treat HCC and avoid its recurrence. Therefore, it is essential to develop treatment approaches that specifically and effectively target hepatic stem cells. Given this, one potential treatment approach is to use particular small interfering RNA (siRNA) to target CSC, disrupting their behavior and microenvironment as well as changing their epigenetic state. The characteristics of CSCs in HCC are outlined in this study, along with new treatment approaches based on siRNA that may be used to target hepatic CSCs and overcome HCC resistance to traditional therapies.

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.

Combined early dynamic 18F-FDG PET/CT and conventional whole-body 18F-FDG PET/CT in hepatocellular carcinoma

OBJECTIVE

To investigate the diagnostic value of early dynamic 18F-FDG PET/CT(ED 18F-FDG PET/CT) combined with conventional whole-body 18F-FDG PET/CT(WB 18F-FDG PET/CT) in hepatocellular carcinoma (HCC), as well as the difference of early dynamic blood flow parameters and maximum standardized uptake value (SUVmax) in HCC patients with/without liver cirrhosis or microvascular invasion (MVI).

METHODS

Twenty-two consecutive patients (mean age 57.8 years) with 28 established HCC lesions (mean size 4.5 cm) underwent a blood flow study with an 18F-FDG dynamic scan divided into 24 sequences of 5 s each and a standard PET/CT scan. On the ED PET/CT study, an experienced PET/CT physician obtained volumes of interest (VOIs) where three blood flow estimates (time to peak [TTP], blood flow [BF], and hepatic perfusion index [HPI]) were calculated. On the WB PET/CT study, a VOI was placed on the fused scan for each HCC and maximum standardized uptake value (SUVmax) was obtained. Comparison of blood flow estimates, SUVmax, and tumor/background ratio (TNR) was performed among HCCs with and without angioinvasion, as well as HCCs in cirrhotic and non-cirrhotic liver.

RESULTS

Compared with WB 18F-FDG PET/CT alone, ED combined with WB 18F-FDG PET/CT can significantly increase the detection rate of moderately differentiated and poorly differentiated HCCs (both P < 0.05). HPI was higher in HCCs in patients with liver cirrhosis than those without liver cirrhosis (P = 0.044). There was no significant difference in TTP, BF, SUVmax, or TNR between HCCs in patients with liver cirrhosis and those without liver cirrhosis. There was no significant difference in blood flow estimates or SUVmax in background liver parenchyma between patients with and those without cirrhosis. TTP was shorter in HCCs with MVI than without MVI (P = 0.046). There was no significant difference in BF, HPI, SUVmax, or TNR between HCCs with MVI and without MVI. There was no significant difference in blood flow estimates or SUVmax in background liver parenchyma between patients with and those without MVI.

CONCLUSION

ED combined with WB 18F-FDG PET/CT can significantly increase the detection rate of moderately differentiated and poorly differentiated HCCs. HPI was significantly higher in HCCs in patients with liver cirrhosis than those without liver cirrhosis. TTP was significantly shorter in HCCs with MVI than without MVI.

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.

FAP-targeted PET imaging in gastrointestinal malignancies: a comprehensive review

F18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) plays a crucial role in tumour diagnosis, staging, and therapy response evaluation of various cancer types and has been a standard imaging modality used in clinical oncology practice for many years. However, it has certain limitations in evaluating some particular gastrointestinal cancer types due to low FDG-avidity or interphering physiological background activity. Fibroblast activation protein (FAP), a protein of the tumour microenvironment, is overexpressed in a wide range of cancers which makes it an attractive target for both tumour imaging and therapy. Recently, FAP-targeted radiopharmaceuticals are widely used in clinical research and achieved great results in tumour imaging. Considering the limitations of FDG PET/CT and the lack of physiological FAP-targeted tracer uptake in liver and intestinal loops, gastrointestinal cancers are among the most promising indications of FAP-targeted imaging. Herein, we present a comprehensive review of FAP-targeted imaging in gastrointestinal cancers in order to clarify the current and potential future role of this class of molecules in gastrointestinal oncology.

Potential and Clinical Significance of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for Evaluating Liver Cancer Response to Lenvatinib Treatment

BACKGROUND

The sensitivity of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in hepatocellular carcinoma (HCC) is low; however, clinical evidence demonstrating its prognostic value in patients with HCC has recently been reported. This study aimed to assess the value of 18F-FDG-PET/CT as a tool for evaluating the response of HCC to lenvatinib treatment.

METHODS

We evaluated 11 consecutive patients with HCC diagnosed by dynamic CT or magnetic resonance imaging combined with 18F-FDG-PET/CT from April 2018 to December 2019. The tumor-to-normal liver ratio (TLR) of the target tumor was measured before and during the course of lenvatinib treatment with 18F-FDG-PET/CT (pre and post analysis, respectively), with a TLR ≥2 classified as PET-positive HCC. At the time of each evaluation, we also used the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, the modified RECIST (mRECIST), and the tumor marker alfa-fetoprotein (AFP).

RESULTS

Of 11 patients, 3 (27%) and 8 (73%) had an objective response to lenvatinib treatment at the time of post-analysis by RECIST 1.1 and mRECIST, respectively. There were 3 (27%) and 7 (64%) patients with PET-positive HCC at the time of pre- and post-analysis, respectively. There was a significant correlation between the rates of change in AFP and TLR during lenvatinib treatment (r = 0.69, p = 0.019). Based on these results, we were able to perform liver resection on 4 patients with PET-positive HCC as conversion therapy. Three samples from these patients showed poorly differentiated tumors.

CONCLUSION

18F-FDG-PET/CT has potential as an evaluation tool for describing biological tumor behavior and reflecting disease progression, location, and treatment response. This modality may provide useful information for considering prognosis and subsequent therapy.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cancer Stem Cells: A Potential Breakthrough in HCC-Targeted Therapy

Cancer stem cells (CSCs) are subpopulations of cells with stem cell characteristics that produce both cancerous and non-tumorigenic cells in tumor tissues. The literature reports that CSCs are closely related to the development of hepatocellular carcinoma (HCC) and promote the malignant features of HCC such as high invasion, drug resistance, easy recurrence, easy metastasis, and poor prognosis. This review discusses the origin, molecular, and biological features, functions, and applications of CSCs in HCC in recent years; the goal is to clarify the importance of CSCs in treatment and explore their potential value in HCC-targeted therapy.