Value of ¹⁸F-FDG-PET/CT in the detection of recurrent hepatocellular carcinoma after hepatectomy or radiofrequency ablation: a comparative study with contrast-enhanced ultrasound

A Diagnostic Nomogram Based on 18F-FDG PET/CT for Bone Metastasis of Gastric Cancer

Purpose: To develop an effective diagnostic model for bone metastasis of gastric cancer by combining ¹⁸F-FDG PET/CT and clinical data.

Materials and Methods: A total of 212 gastric cancer patients with abnormal bone imaging scans based on ¹⁸F-FDG PET/CT were retrospectively enrolled between September 2009 and March 2020. Risk factors for bone metastasis of gastric cancer were identified by multivariate logistic regression analysis and used to create a nomogram. The performance of the nomogram was evaluated by using receiver operating characteristic curves and calibration plots.

Results: The diagnostic power of the binary logistic regression model incorporating skeleton-related symptoms, anemia, the SUVmax of bone lesions, bone changes, the location of bone lesions, ALP, LDH, CEA, and CA19-9 was significantly higher than that of the model using only clinical factors (p = 0.008). The diagnostic model for bone metastasis of gastric cancer using a combination of clinical and imaging data showed an appropriate goodness of fit according to a calibration test (p = 0.294) and good discriminating ability (AUC = 0.925).

Conclusions: The diagnostic model combined with the ¹⁸F-FDG PET/CT findings and clinical data showed a better diagnosis performance for bone metastasis of gastric cancer than the other studied models. Compared with the model using clinical factors alone, the additional ¹⁸F-FDG PET/CT findings could improve the diagnostic efficacy of identifying bone metastases in gastric cancer.

Interventional real-time optical imaging guidance for complete tumor ablation

The aim of this study was to develop an interventional optical imaging (OI) technique for intraprocedural guidance of complete tumor ablation. Our study employed four strategies: 1) optimizing experimental protocol of various indocyanine green (ICG) concentrations/detection time windows for ICG-based OI of tumor cells (ICG cells); 2) using the optimized OI to evaluate ablation-heat effect on ICG cells; 3) building the interventional OI system and investigating its sensitivity for differentiating residual viable tumors from nonviable tumors; and 4) preclinically validating its technical feasibility for intraprocedural monitoring of radiofrequency ablations (RFAs) using animal models with orthotopic hepatic tumors. OI signal-to-background ratios (SBRs) among preablation tumors, residual, and ablated tumors were statistically compared and confirmed by subsequent pathology. The optimal dose and detection time window for ICG-based OI were 100 μg/mL at 24 h. Interventional OI displayed significantly higher fluorescence signals of viable ICG cells compared with nonviable ICG cells (189.3 ± 7.6 versus 63.7 ± 5.7 au, P < 0.001). The interventional OI could differentiate three definitive zones of tumor, tumor margin, and normal surrounding liver, demonstrating significantly higher average SBR of residual viable tumors compared to ablated nonviable tumors (2.54 ± 0.31 versus 0.57 ± 0.05, P < 0.001). The innovative interventional OI technique permitted operators to instantly detect residual tumors and thereby guide repeated RFAs, ensuring complete tumor eradication, which was confirmed by ex vivo OI and pathology. In conclusion, we present an interventional oncologic technique, which should revolutionize the current ablation technology, leading to a significant advancement in complete treatment of larger or irregular malignancies.

Sublethal heat stress-induced O-GlcNAcylation coordinates the Warburg effect to promote hepatocellular carcinoma recurrence and metastasis after thermal ablation

The malignant transformation of residual hepatocellular carcinoma (HCC) cells after thermal ablation is considered as the main factor promoting postoperative HCC progression, which greatly limits the improvement of long-term survival, and at present there is no effective targeted therapeutic strategies. The Warburg effect is a metabolic feature correlated highly with malignant transformation (e.g. epithelial-to-mesenchymal transition [EMT]). Here, we showed that sublethal heat stress triggered a stronger Warburg effect of HCC cells, which contributed to the thermotolerance and invasion of HCC cells. Sublethal heat stress-induced O-GlcNAcylation was involved in this process. Such enhanced Warburg effect in HCC cells may be eliminated through O-GlcNAcylation inhibition, resulting in impaired thermotolerance and EMT, and thereby preventing tumor recurrence and metastasis of HCC-bearing mice after insufficient thermal ablation. Finally, we present evidence that sublethal heat stress-induced O-GlcNAcylation regulates the Warburg effect in HCC cells by promoting hypoxia-inducible factor 1α (HIF-1α) stability. In conclusion, the present study suggests that O-GlcNAcylation coordinates the Warburg effect to promote HCC progression after thermal ablation, which may serve as a novel potential target for controlling postoperative HCC recurrence and metastasis.

The value of contrast-enhanced ultrasound in predicting postoperative recurrence of hepatocellular carcinoma: A protocol for systematic review and meta-analysis

BACKGROUND

As one of the key factors, postoperative recurrence of hepatocellular carcinoma (HCC) influences the therapeutic effects and survival period of patients. Therefore, the early diagnosis of postoperative recurrence of HCC plays an important role in improving the therapeutic effects and prognosis. Contrast-enhanced ultrasound (CEUS) plays an important role in the early diagnosis of postoperative recurrence of HCC. However, the accuracy of CEUS in predicting postoperative recurrence of HCC is still controversial. Therefore, in this study, a meta-analysis was carried out to further evaluate the accuracy of CEUS in predicting postoperative recurrence of HCC, thus providing evidence support for the early diagnosis of HCC.

METHODS

The literatures on the CEUS diagnosis of postoperative recurrence of HCC were collected by searching China National Knowledge Infrastructure, Wanfang, China Biology Medicine disc, PubMed, EMBASE, Cochrane Library, and Web of Science on computer. The retrieval time is set from the start of the database until April 2021. The meta-analysis of the literatures that meet the quality standards was conducted by Stata 16.0 software.

RESULTS

The results of this meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

This study will provide evidence support for the accuracy of CEUS in the diagnosis of postoperative recurrence of HCC.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also should not damage participants' rights. Ethical approval is not available. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/HB46W.

Positron-emission tomography for hepatocellular carcinoma: Current status and future prospects

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer mortality worldwide. Various imaging modalities provide important information about HCC for its clinical management. Since positron-emission tomography (PET) or PET-computed tomography was introduced to the oncologic setting, it has played crucial roles in detecting, distinguishing, accurately staging, and evaluating local, residual, and recurrent HCC. PET imaging visualizes tissue metabolic information that is closely associated with treatment. Dynamic PET imaging and dual-tracer have emerged as complementary techniques that aid in various aspects of HCC diagnosis. The advent of new radiotracers and the development of immuno-PET and PET-magnetic resonance imaging have improved the ability to detect lesions and have made great progress in treatment surveillance. The current PET diagnostic capabilities for HCC and the supplementary techniques are reviewed herein.

18F-FDG PET with or without CT in the diagnosis of extrahepatic metastases or local residual/recurrent hepatocellular carcinoma

The aim of the present study was to meta-analyze the literature on the diagnostic value of 18-fluorodeoxyglucose (F-FDG) positron emission tomography (PET) with or without computed tomography (CT) in detecting extrahepatic metastases or local residual/recurrent hepatocellular carcinoma (HCC).Systematic review of literature in MEDLINE, Embase, and Cochrane databases was conducted in March 2017, and relevant studies analyzing the diagnostic performance of F-FDG PET with or without CT were meta-analyzed.Meta-analysis was carried out on data from 11 studies involving 572 patients. F-FDG PET, with or without CT, showed pooled sensitivity of 64% and pooled specificity of 95%. Pooled sensitivity was similar with CT (74%) or without (52%; P = .279). Similarly, pooled specificity was comparable with CT (93%) or without 95% (P = .481).F-FDG PET, with or without CT, shows relatively low sensitivity but high specificity for diagnosing extrahepatic metastases or local residual/recurrent HCC. Adding CT to F-FDG PET may improve diagnostic performance, but the available evidence suggests that the improvement is not statistically significant.

Efficacy of contrast-enhanced FDG PET/CT in patients awaiting liver transplantation with rising alpha-fetoprotein after bridge therapy of hepatocellular carcinoma

OBJECTIVE

To assess the diagnostic accuracy and illustrate positive findings of contrast-enhanced fluorine-18 fluoro-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) image in patients awaiting liver transplantation (LT) with rising alpha-fetoprotein (AFP) after bridge therapy of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This prospective study included 100 patients who were waiting for LT and who previously underwent locoregional therapy (LRT) of HCC. These patients had rising AFP levels on a routine follow-up examination awaiting LT. All patients underwent a contrast-enhanced ¹⁸F-FDG PET/CT examination. We calculated for each patient the maximum standardised uptake value (SUVmax) of the tumour and the ratio of the tumoral SUVmax to the normal-liver SUVmax. The diagnostic accuracy and positive contrast-enhanced findings of ¹⁸F-FDG PET/CT were established by histopathology and clinical and imaging follow-up as the reference standards.

RESULTS

Contrast-enhanced ¹⁸F-FDG PET/CT detected tumour relapse in 78 patients (13 patients had intrahepatic lesions, 10 patients had extrahepatic metastases and 55 patients with combined lesions). The sensitivity, specificity and accuracy values of contrast-enhanced ¹⁸F-FDG PET/CT examination in the detection of HCC recurrence were 92.8%, 94.1% and 93%, respectively. A significant correlation was found between the AFP level and SUVmax ratio (r = 0.2283; p = 0.0224). The best threshold for ¹⁸F-FDG PET positivity was >1.21.

CONCLUSION

Contrast-enhanced ¹⁸F-FDG PET/CT is a valuable tool for the detection of intrahepatic HCC recurrence or extrahepatic metastasis following rising AFP levels after LRT of HCC, and should be incorporated during routine workup awaiting LT.

KEY POINTS

• ¹⁸F-FDG PET/CT is a valuable tool for the detection of HCC recurrence • ¹⁸ F-FDG PET/CT should be incorporated during routine workup awaiting liver transplantation • Significant correlation was found between AFP level and SUVmax ratio • The best threshold for ¹⁸ F-FDG PET positivity was >1.21 • The ideal cut-off value for AFP was >202.

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

Backgrounds/Aims

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

Methods

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

Results

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

Conclusions

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

FDG-PET/CT in the Postoperative Period: Utility, Expected Findings, Complications, and Pitfalls

FDG-PET/CT as a modality is increasingly used for detection of recurrence and for restaging in patients with clinical suspicion of malignancy, as well as in patients with elevated tumor markers. However, there are many pitfalls in the interpretation of these scans when the studies are performed after some treatment. Some of these are attributed to normal physiological distribution and are compounded when there are inflammatory changes occurring after surgery. The body's inherent response to the surgical insult results in this inflammation. In addition, there are also complications that can happen following surgery, causing increased FDG uptake. Despite various fallacies, FDG-PET/CT provides valuable information in evaluation of residual and recurrent malignant disease. In this article, we aim to describe some of these postsurgical changes secondary to inflammation, common surgical complications, and finally, the utility of FDG-PET/CT in these patients to detect recurrent disease, even in the background of postsurgical changes.

Imaging evaluation of residual cancer after radiofrequency ablation of hepatocellular carcinoma

Primary liver cancer is one of the most common malignant tumors in the world, and only a few patients have the chance of surgical resection. Radiofrequency ablation (RFA) is a good treatment for patients with unresectable liver cancer. The existence of residual cancer after radiofrequency ablation has a direct impact on the prognosis of patients, so it is important to accurately determine whether there is residual cancer after RFA treatment in order to reduce the local recurrence and prolong the survival time of patients. In this paper, we discuss the evaluation of residual cancer after radiofrequency ablation of hepatocellular carcinoma by ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), digital subtraction angiography (DSA) and nuclear medicine modalities.

The Role of PET Imaging Before, During, and After Percutaneous Hepatic and Pulmonary Tumor Ablation

The combination of anatomic and metabolic information provided by positron emission tomography (PET)/computed tomography makes it an important imaging modality to be obtained in conjunction with percutaneous ablation of primary and secondary malignancies of the lungs and liver. Advantages include more accurate preprocedural staging to determine appropriate treatment options, intraprocedural guidance to target difficult-to-see lesions, and postprocedural detection of residual or recurrent disease. Future applications of PET include strategies for intraprocedural guidance with real-time determination of incompletely ablated tumor, and combined PET/magnetic resonance imaging before, during, and after ablation for greater sensitivity to detect disease.